
BookJl^ 

Copyright ]^°_ 

' CORfRlGHT DEPOSm 



X 



X 



OF READING 
Working Drawings or Blue Prints 




BY 



DAVID McLAIN 



McLAIN'S SYSTEM, Inc. 

MILWAUKEE, WIS., U. S. A. 



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Copyright in the 

United States 

1921 

BY David McLain 

Milwaukee, Wis., U.S.A. 

AND 

Entered at Stationers' 
Hall, London 



JliN I S 1922 

CIA679042 



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PREFACE. 



KnoAving from personal experience that there exists a great 
need for the information contained in these lessons, and being in 
direct touch with good mechanics in all walks of life who are mas- 
ters of their particular trade but lack the important knowledge of 
"^ reading a working drawing, it has been endeavored to arrange 
this course of instruction in such a manner as to make it complete 
and intelligible. We are positive that with persistent effort on 
the student's part, he will be able to absorb this information both 
to his own personal benefit and to his employer's, thereby making 
himself a stronger link in the human chain of producers. 

After glancing over the work, the student may be under the 
impression that the illustrations and descriptive matter as here 
presented are not suited to his particular trade, and therefore of 
nq benefit to him; however, we assure you this is erroneous, as 
the principle involved in the reading of any working drawing, 
as explained and discussed within these pages, is identically the 
same for all classes of working drawings, and is applicable to all 
trades. 

It is a well-kno^vn fact that a person may be well posted on a 
certain subject but lack the faculty to express himself in such a 
way as to impart this knowledge to others so they may understand 
it. We have therefore, borne this in mind and produced this work 
so that it will be readily understood and at the same time inter- 
esting. It should be remembered that all working drawings re- 
quire more or less study, and it is practice in reading them that 
will make the student proficient; therefore do not become dis- 
couraged if you find some subject seemingly difficult to understand. 
We earnestly suggest that you read and re-read each paragraph 
and master each step as you proceed and we feel confident of your 
success. 

The object of these instructions is to give you a general knowl- 
edge of how to read a working drawing, as it is not our aim to teach 
you how to become a draftsman or engineer. By following the in- 
structions closely and referring to the illustrations you will master 
the information contained in these pages and will be able to read a 
fairly complicated Avorking drawing. 



McLAIN'S SYSTEM, Inc. 



A UNIVERSAL LANGUAGE 



In the mechanical world the reading of working 
drawings is just as important as the reading of words 
in a language, but a knowledge of reading drawings 
once acquired has a still greater value, as the inter- 
pretation of working drawings is universal. 



LESSON ONE 



IMPORTANCE OF CAREFUL STUDY. 

The careful student must be impressed with the necessity of 
knomng things. The way to know a thing is to study it, just as 
you studied your books when learning to read. First you learned 
the simple words — how they look^ — what letters of the alphabet 
are used in spelling them — how the words are pronounced, etc. 
Anyone who is ambitious enough to study these lessons can learn 
to read working drawings. 

To assist the student in doing this, a variety of simple working 
drawings has been selected for analysis. Altho they by no means 
cover all classes of work, those selected are especially good exam- 
ples in bringing out the point in question. Carefully study each 
working drawing as well as the descriptive matter pertaining to it. 

Important — To understand an object shown on a working 
drawing, the student must remember that it is necessary to refer 
to more than one view of the object — no single view will explain 
a drawing fully unless it is a very simple object, such as a solid 
cylinder having proper notations for diameter, etc. 



WHAT IS A WORKING DRAWING? 

A working drawing may be defined as a drawing made to rep- 
resent an object — ^not as it appears to the eye in perspective view — 
but showing the actual relation of all surfaces and points to each 
other, using a combination of plan, side, end or bottom views. 

Blue prints are reproductions of original working drawings. 

WORKING DRAWINGS CLASSIFIED. 

All working dramngs may be divided into two classes — general 
or assembly drawings, and detail drawings. 

General or assembly drawings show the relative position of the 
various parts in relation to one another or the general outline 
of the finished assembled product with its component parts. On 
an assembly drawing, the over-all dimensions and the more im- 
portant distances between center lines are usually shown. 



Detail drawings show the exact shape and size of each com- 
ponent part used to make up a finished product. A detail drawing 
should be made complete in every respect showing sufficient dimen- 
sions and notations to enable the workman to complete his par- 
ticular operation in its production without the necessity of per- 
sonal explanation. 

It is the general practice to make detail working drawings with 
all necessary dimensions for the various operations; however, on 
very complicated work separate drawings are sometimes made for 
the pattern maker, machinist and blacksmith, giving only the di- 
mensions which pertain to his particular trade. 

LINES. 



L/NE 






PfifiFILLEl. LjN£^ 



DOTTE.D Unb 



The above represents several different styles of lines. 

A line is a mark having length but neither breadth nor thickness. 

A straight line is the shortest distance between any two points 
assuming there are no obstructions. 

A curved line changes its direction continually; 

Parallel lines are the same distance apart thruout their entire 
length. 

Dotted lines are short portions of lines, each being separated. 

Dash lines are long portions of lines, each being separated. 

6 



DESCRIPTION OF LINES APPEARING ON WORKING 

DRAWINGS. 

Working drawings are produced by a combination of straight, 
curved and dotted lines arranged to show the outline and details 
of an object. It has been found that different kinds of lines are 
necessary to more clearly explain the various surfaces and points of 
the objects under discussion. For this purpose a series of different 
lines has been adopted. 



Center line — The above represents a center line which is usually 
drawn thru the center of the object. If the object is symmetrical, 
this line is drawn thru the exact center ; if, however, it is not sym- 
metrical, the line is dra^^^i thru its established center and forms 
the base for the taking of dimensions. . 



General line. — This represents the style of line usually employed 
to indicate the outline of the object and generally is medium heavy. 



Dotted line. — A dotted line on a drawing indicates that a certain 
portion of the object exists, but is hidden from view. 



Long dash line. — This line is used to indicate the location of a 
cross sectional view. 

It is not always the practice to use the conventional represen- 
tation of lines as here noted, and any deviation will readily be 
detected, as for example, the center line may be represented by a 
line, thus 

instead of 



The general outline may also be represented with very heavy lines 
in place of the medium heavy. 

In these lessons all lines mentioned as being horizontal are lines 
running from left to right, thus 



/-{or I z.oNT^L- Lz/s/e: ^ 



All lines mentioned as vertical lines run in the direction of top 
to bottom of sheet, thus 



KINDS OF DRAWINGS. 

There are several types of drawings, namely — ^perspective, 
isometric, cabinet and orthographic. 




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Fig. 1 represents a true perspective drawing of a cube. In true 
perspective drawings the points or surfaces farthest from the point 
of observation are the smallest. The eye must be in a stationary 
position for all types of perspective draAvings. 

A condensed method of constructing the perspective of Fig. 1 
is illustrated by the light lines, converging to a common point on 
an established vanishing line. 

Fig. 2 represents an isometric drawing of a cube. This type of 
drawing shows the true length of each line and is a modification 
of the perspective drawing in Fig. 1. Generally three surfaces are 
shown, a top and tAvo adjacent sides. 

Fig. 3 is a cabinet projection of this cube. In this drawing one 
face of the cube is shown full view; the side surface is shown in- 
clined upward and to the right. This drawing differs from the 
isometric drawing .in so far as the side and top are not shown in 
full length, but approximately half. ' 

All drawings in these lessons, sho\ATi as in Figs. 1, 2 or 3, for 
convenience will be classified perspective drawings. 

Fig. 4 represents an orthographic projection of this same cube. 
This type of drawing will be classified as working drawing views 
in these lessons. This figure represents the projection of the top 
and front of cube and is the type of drawing which is used in the 
making of all working drawings. 

Mechanical drawing is a language of lines, arranged to pro- 
duce working draAving vicAvs — and the interpretation is universal. 



8 



SHADED LINES. 




Fig. 5 

Fig. 5 represents shaded lines. These are seldom used on 
working drawings. All patent and sometimes assembly drawings 
of working parts are made using shaded lines. The shaded line is 
used to assist in a better understanding of the character of a par- 
ticular part and will show whether the surface is raised, depressed 
or represents a hole. For example, let us assume that Fig. 5 repre- 
sents a flat board upon which a coin or similar object is placed in 
the upper left hand corner, while in the lower right hand corner 
a round hole is cut. 

It is always assumed that rays of light fall from the upper left 
hand towards the lower right hand comer in the direction of the 
diagonal lines. In passing over the coin the light rays will throw 
a shadow around the lower right half jof the coin, also showing 
at a glance that this shadow is produced by the raised surface. 
Likewise, we have the opposite condition when the rays pass over 
the hole as indicated in the lower right hand corner. The light 
will throw a shadow along the upper left hand of the cut-out por- 
tion, indicating a hole. This also applies to a depressed surface. 



9 



LINE SHADING. 



A series of lines is sometimes employed to show that a certain 
object is rounded, as for example Fig. 6. 




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The above line shading aids in indicating a solid cylinder. 
Again, we will assume that the light comes from the top, producing 
a shadow along the lower surface of the cylinder. The horizontal 
lines are placed closer together as they near the lower edge of the 
cylinder indicating the magnitude of the shadow. 

Fig. 7 illustrates the use of line shading on a vertical rounded 
surface — the lines being placed closer together- as they near the 
edge which is farthest away from the source of light. 




Line 3HRDinci 



Sectional View of Chipping Hammer 



^HUOtO LiNEi 



The sectional view of chipping hammer illustrates the use of 
line shading and shaded lines, each being marked on the illustra- 
tion. 

Your attention is also called to the line shading of the cylinder 
walls, the lines being placed closer together as they near the top, 
which indicates it is hollow. 

For depressed cylindrical surfaces the line shading is opposite 
of that shown in Figs. 6 and 7. 



10 




EXAMINATION 
LESSON 1 

1. What are parallel lines? 

2. Are horizontal and vertical lines shown in Fig. 4? 

3. What is the difference in construction between a center line 
and a general line? 

4. Are shaded lines generally used on working drawings? 

5. What is the advantage of using line shading? 



th 



11 



LESSON TWO 



IMAGINATION A VALUABLE ASSET. 

Imagination will be found to be your best assistant in this work, 
and by the aid of the projections, picture a model of the object 
represented. 

An object, or solid, of any conceivable shape may thus be re- 
solved into its elementary parts or points. The drawing of the 
object, then, will consist simply of locating the positions of these 
points on the dramng. You may have drawings that require the 
location of a hundred or more of these points, depending entirely 
on the form or shape of the object in question, but the principles 
are the same in all cases. 

If, after resolving an object in this imaginary way, you will 
carefully study or imagine the proper location of these points in 
their relation to the object itself, defining their positions on the 
drawing, one at a time, much that may appear complicated at first 
sight will resolve itself into very simple and comparatively elemen- 
tary work. Complicated work is usually nothing more nor less 
than the aggregation of a number of simple operations that appear 
complicated only because they are combined. 

It is in the imaginary way thus described that you are directed 
to picture each figure as presented for the reading of working 
drawings. This part of the study is almost entirely the work of 
the imagination, as will be noted, but it should be practiced for 
the sake of the assistance it will render later on. 

As the working drawing is produced on a flat surface, it is 
necessary to use your imagination to make th^ lines and views lift 
up from the paper. When a clear-cut mental picture has been 
formed, the dimensions should be studied until understood. Next 
all the lettered text should be read and considered. 

In order to more readily understand a working drawing, it will 
be necessary to imagine or picture the object under discussion, and 
after a little practice you will be surprised hoAV quickly this can 
be mastered. 

13 



DEVELOPING THE IMAGINATION. 

We suggest that you take some familiar object, say a hammer; 
close your eyes and picture the outline of it. Try several other 
objects. Such practice will greatly assist in a better understanding 
of the principle of reading working drawings. 

It is also important that you learn to look at an object and 
see only a view representing a side, or a top, an end or bottom at a 
time. For example, take the hammer and hold it level with the eye, 
so that only the side can be seen ; then look directly at the top, not 
seeing either side. This is exactly what a working drawing would 
show — only one view at a time and never in perspective. Of 
course, it is not always possible to take the various objects that 
are shown on a drawing and place yourself in a position so that 
only one view is visible at a time. 




Let us assume a pattern maker is called upon to make a pattern 
to dimensions on a certain drawing. You will readily see that it 
will be absolutely necessary for him to be able to read a working 
drawing correctly and to form a mental picture of the finished 
object as he has no object to look at. 

It is important that you clearly understand each topic and illus- 
tration as you proceed, as each is the stepping stone to the next, 
therefore if you master the subjects in their order, we feel confident 
that you will be able to read the final drawing of the instructions 
submitted without difficulty. 

14 



CARE IN THE MAKING AND READING OF WORKING 

DRAWINGS. 

It is important that care be exercised in the reading of a work- 
ing drawing as sometimes a draftsman may become careless and 
not place dimension lines on a drawing correctly, which may cause 
much confusion. For example, the dimension lines here shown 
are correctly and incorrectly placed. Dimension lines with the 
arrows should always extend to meet the lines to which they refer. 



J^CORRE'C^f 



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Much confusion is also caused by carelessness on the part of 
the draftsman in writing his dimensions. For example, assume 
he wishes a certain dimension to be 



// 
/6 



but writes it thus, 



//. 



It 



'f(h 



it may be mistaken for 1tV'> therefore it is always advisable to 
use the horizontal line when writing fractions, instead of the 
diagonal. 

POSITION OF EYE FOR WORKING DRAWING VIEWS. 

Fig. 8. The object of this illustration is to show the position 
of the eye when making working drawing projections, and is shown 
in a direct horizontal line with each and every point along the 
entire height and mdth of the object. 

This figure shows a tall, square, tapered chimney in perspective 
view, also an elevator capable of traveling a distance equal to the 
height of the chimney. 

Disregard the elevator for the present. Looking at the chimney 
from the angle as here sho\\Ti, the vertical line **c d" is nearest to 
your eye and therefore the longest; the lines '^f e and a b" being 
farther away, are all shortened in accordance to one of the rules 
for perspective drawing which says that *'all horizontal lines of 
an object vanish to a common point called the vanishing point 
located on a vanishing line, and sometimes called the horizon." 

Perspective drawing is a study in itself and we will not at- 
tempt to discuss it in these lessons. 

15 



We have shown the outline of a man on the elevator and it is 
assumed that he' has closed one eye and is in such a position that 
the line of vision of the other eye is in a direct line with the 
edge E of chimney, not being able to see either the right or left 
hand side of chimney. The horizontal line from his eye to a point 
on the edge E is here shown and marked ''line of vision." 




Vanishing Line 



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Imagine that the elevator had started at the bottom, the man's 
line of vision being at point **a'\ As the elevator travels up he 
sketches the vertical edge E on the paper ; when his eye is in 
a horizontal line with the top point **b" he stops the elevator, walks 
across to the other side of it, keeping his eye in line on the edge 
*'b c" and sketches this line. He then starts down, keeping his 



16 



line of vision on the edge F, sketching each point as he moves 
do^vn until he reaches the bottom point ''d" Avhere he stops and 
walks back to the other side of elevator, keeping his eye on the 
line "d a," and sketching same. 

His completed sketch of the front view will be as illustrated at 
the right and marked **Fig. 8 A/' the corresponding edges and 
points being marked with the same letter in both views. 

This illustrates the imaginary position of the eye for all working 
drawing views and regardless of the height or width, the line of 
vision is always in a direct horizontal line when projecting any side 
or end of an object. 

The explanation of Fig. 8 is very important and you should 
clearly understand this before proceeding further as it is absolutely 
essential to know the location of the imaginary position of the eye 
when making a working drawing view. 

The horizontal position of the eye applies not only to the outline 
of the object as shown and explained, but also to any point on the 
surface of the particular face you may be sketching. This will 
be better understood after you have studied the illustrations and 
descriptive matter pertaining to Figs. 9, 10 and 11. 

As mentioned, Fig. 8 A corresponds to the working drawing- 
view of one of the exterior faces of this chimney and is designated 
as the front view. 

Imagine that the elevator is moved around so that it is directly 
opposite the right hand side of chimney, and the elevator and man 
moved up and down in a similar manner as mentioned when the 
front view^ was sketched^the man sketching the outline of the 
right hand side or face. 

A view similar to that shown in Fig. 8 A would be produced to 
represent the right hand side of the chimney and the letters ''d e" 
would designate the two lower corners and ^'c f" the two upper 
corners. This view should then be placed to the right of Fig. 8 A 
and both views would Tcpresent the exterior working drawing, views 
of the front and right hand side of the chimney. 

The horizontal position of the eye applies to the making of 
front, side or end views. The position of the eye for a top view 
will be explained under Fig. 11. 

Important — It should be remembered that the eye must be in 
a direct horizontal line with all points along the outline, also with 
all points on the surface or face of the object you are sketching 
when making a front, side or end view of an object. 

17 



ILLUSTRATION EXPLAINING THE PROJECTION OF A 

DEPRESSED SURFACE. 




Ff<^-/o. 



Fig. 9. Suppose that A and B are glass plates placed at right 
angles to each other and bolted together at the corners with hinges 
— the object C being placed back of these glass plates as shown. 

Object C represents a solid and may be made of any material 
cut to the shape shown. We call your attention particularly^ to 
the relative position of the surface D to E — the surface D being 
some distance back of E. In the projections of various surfaces 
of an object, all surfaces as D and E are brought to the same plane. 
To illustrate this, we have projected the various points of this 
object to the glass plate A and have indicated the correct projec- 

18 



tion on the plate. — Kegardless of how far back the surface D may 
have been located on the object C, these surfaces are always brought 
to the same plane to produce working drawing views. It is im- 
portant that you understand this as it is one of the first steps in the 
reading of working drawings. 

Object C is here shown in perspective, or as it Avould actually 
appear when looking at it from an angle. A perspective view of 
an object is obtained by looking at it from an angle so that two 
or more views are visible at one time. Working draAvings are 
produced by looking at an object so that a view representing only 
one of its sides, top, end or bottom, is visible at a time — all de- 
pressions and extensions being brought to the same plane, and the 
eye placed directly in line with each point on its surface or outline 
regardless of its length or height. 

To illustrate this w^e have shown the position of the eye at 
various points along the length and height of the object at the 
left and right of this figure. 

To make this clearer we suggest that you take a book and 
place it flat upon a table, and look at it from an angle so that the 
top, end and back can be seen. This view would be called a per- 
spective. Pick up the book, hold it flat with the end towards you 
and at a level with the eye, close one eye and you will see the end 
only which would correspond with one view of a working drawing. 
Coming back to the illustration Fig. 9 keep in mind the experiment 
with the book and refer to the projection of the side surface F 
of object C on plate B, then you Avill readily understand how this 
projection is produced and likewise the projection of the surfaces 
D and E on the glass surface A. 

Fig. 10. Now suppose that we have opened these plates and 
then imagine that the projected surfaces D, E and F have been 
outlined on the glass plate as shown. In opening the glass plate 
the arrows indicate the path of travel of the outer edges of the 
glass plates and also the assumed path of the outline of the object. 
After these plates have been completely opened the lines g, h and j 
Avill show the corresponding points of the end and side views. These 
final views of the surfaces D, E and F are the correct working 
drawing projections of the original object C in Fig. 9 and illustrate 
one method of producing a working drawing view. 

19 



ANOTHER EXAMPLE ILLUSTRATING THE POSITION OF 
EYE FOR WORKING DRAWING VIEWS. 




r'^ -^i 



In the making and reading of a working drawing, it is always 
supposed that the eye is in direct line with each point or surface, 
vertically for a top view and horizontally for a side or end vicAv — 
for example Fig. 11. Let us imagine that we have placed a block 
of iron with a shelf projection on one side into a solid cube of glass. 

We mil now explain the projection of the shelf surface : 

It will be seen that the top surface of this shelf projection is 
shown some distance from the top of the iron block proper; how- 
ever, when making a projection for a working drawing, all depres- 
sions and extensions are brought to the same plane, as shown on 
the top surface of the glass cube; likewise when looking at the 
end, the eye must be in a horizontal position with each point re- 
gardless of the height of the object. 

Your attention is called to the various positions of the eye at 
the side to illustrate this point — then by projecting each point to 
the end surface of the glass cube, or same plane, a view is pro- 

20 



duced as shown at the end surface of cube. Likewise the side 
view is projected to the surface of glass cube in the same manner. 
The object having no depressions or extensions on its side has 
identically the same outline in the side view as the original iron 
block. 



g^ 



EXAMINATION 
LESSON 2 

1. Is the man in Fig. 8 supposed to see either side of chimney in 
making his working drawing of the front view? 

2. What kind of lines are shown in the illustration of hammer on 
page 14. 

3. Fig. 9. (a) Does the projection of the surfaces D , and E 

on the glass plate A show how far back the sur- 
face D is in relation to E ? 
(b) If not, does this show on glass plate B 1 

4. Fig. 11. (a) How many views indicate the distance shelf pro- 

jects beyond the block proper? 

(b) Name them. # 

(c) What type of drawing does the outline of glass cube 
represent ? 



21 



LESSON THREE 



PROJECTIONS. 

One important subject in these lessons comes under the title 
of ''Projections," as it is the key to the understanding of working 
drawings. 




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Fig. 12 represents a box, open at the back, and for the sake of 
illustration, we have placed hinges along the four edges of the 
front and have supposed that the sides, top and bottom can sAving 
on these ; the box has also been marked front, top and right hand 
side. In addition you will note the front of box has a large hole 
in the center, the top a smaller hole towards the rear, and the right 
hand side, a square hole. Left hand side and bottom have no holes. 

In Figs. 12, 13 and 14 we have attempted to show only how 
the exterior surfaces are projected, paying no attention to the 
thickness of the walls. 

Fig. 13 shows the same box as Fig. 12 except that the top of box 
is opened, both sides are spread out and the bottom is dropped; 
the arrows indicate the path of the outer edges. You will readily 
understand by looking at the front view that the large hole in cen- 
ter corresponds with the front in the perspective view; the top and 
right hand side correspond with the top and right hand side in the 
perspective view. Note the relative position of all the views in 

23 



relation to the front — ^namely, that the right hand side is placed 
to the right side of the front, top at the top, and bottom at the bot- 
tom of front view. It is important that you clearly understand the 
relation of these views to the front. 

In Fig. 14 we have removed the hinges and separated each view 
from the front of the box. The same relation of top, bottom and 
sides t© the front view exists as in Fig. 13. 






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Again referring to Fig. 12, if you will imagine that this box is 
placed in such a position that when looking at the front you will 
not see top, sides nor bottom, you will have an outline as shown 
in the middle of Fig. 14, marked ''front." If you will look at 
the side so as not to see any of the other surfaces, you will see an 
outline as shown at the side, and by placing yourself directly over 
the top so that no other surface can be seen, you will get a view 
as shown, and marked ''top." 

It is important that you train your imagination to see a view 
which represents the surface and outline of only one of its faces — 
either a side, an end, the top or bottom of the object at a time. 



24 



METHOD OF PROJECTING WORKING DRAWING VIEWS. 





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The illustration marked Fig. 15 represents a solid block of 
wood with a hole thru its full length. You will have no difficulty 
in understanding this view as it is what is termed a ''perspective'* 
and shows this block as it would actually appear, viewed from an 
angle. 

Fig. 16 illustrates the fundamental principles of producing a 
working drawing. You will note that, it does not resemble the 
view in Fig. 15. In order to learn to read a working drawing, it 
will be necessary that you place yourself squarely in front of the 
object so that sides, top and bottom will not be seen and you ^\dll 
see a view similar to that shown at A, Fig. 16, marked ''front view." 

Again, assume this block is placed in such a position that you 
will see only the side — you mil then see a \dew as at B, Fig. 16, 
marked "side view." 

View C, Fig. 16, is a top vicAv and shows only the top o:^this 
block, were it placed in such a position that front, back and sides 
were not visible. The rear and bottom views are not necessary as 
rear would be the same as the front and bottom the same as the top. 

You will note that the hole shown as a circle in view A is indi- 
cated on view B by two parallel dotted lines, which also show that 
this hole extends thru the full length of the block. 

On view C the dotted parallel lines again indicate the hole. 



25 



Remember, working drawings are never shown in perspective, 
but always as in Fig. 16 and all views of working drawings are 
generally placed in relation to front, as shown. A top view, or 
perhaps a side view, is not always necessary; in this ease either 
the side or the top would have been sufficient. Then again, in very 
complicated drawings all four sides and several cross sectional 
views may be necessary. 




Straight eJpqe: 



r^<^-n 



Fig. 17. (Also refer to Fig. 16.) In this figure we have shown 
how the upper edge of the hole in the front view is projected to 
the side view. You will note the straightedge is placed horizontally, 
the upper edge of this straightedge just touching the top of the 
circle which point, projected horizontally, corresponds to the dotted 
line in the side view and indicates that the dotted line is the correct 
projection of the upper edge of the hole and also that this hole 
extends thru the full length of the block. 



26 



Any point or surface may be projected in this manner, horizon- 
tally between front and side views, and vertically between top and 
front views. 







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Fig. 18 illustrates the method of projecting this same hole from 
the front ^dew to the top view. The straightedge is just touching 
the extreme left hand edge of the circle (see front view). This 
point projected to the top view is indicated by the dotted line. 

The 'eye should be trained to do exactly what the straightedge 
is used for in both Figs. 17 and 18. 

In views as here placed, all points, lines or surfaces are projected 
horizontally from front to side view and vertically from front to 
top view. 

27 - 



Next, let us take this same block and cut out a portion of the 
upper right hand comer as shown in the perspective view. Fig. 19. 




p^-19 




ri<k-^o 



The front view of working drawing shoAvs this cut-out portion in 
upper right hand corner. In the side view B, Fig. 20, you will note 
the full line marked d corresponds with line d on view A. It is 
shown as being a full line on view B because the line of this surface 
can be seen when looking at the side of block. Here again, the 
depressed surface is brought to the same plane (see vicAv B) as 
discussed under Fig. 11. Referring to the top view C, Fig. 20, 
line e corresponds with line e on view A, the depressed surface d 
in view A having been brought to the same plane. Each line has 
its corresponding surface in one view or another, and you should 
study each line to determine just what surface or point it represents 
on the various views. 



28 




3t^/^!^HT£D4^ 




rj<^-2i 



Fig. 21 again illustrates, with the use of a straightedge, how 
the surface d is projected from the front to the side view. 

Fig. 22 illustrates the projection of the surface e from the front 
to the top view. 

Your attention is called to the dotted line f directly in front 
of the straightedge. This line indicates the projection of the right 
hand edge of the hole. Note the relative location of surface e to 
the right hand edge of the hole in the front view. 

It is good practice to note the relative positions of the various 
points or surfaces in one of its views as this will be a helpful guide 
in locating the various points on the corresponding views. 



POINTS OR SURFACES PROJECTED HORIZONTALLY. 



Whenever two views are placed to either right or left of one 
another, all corresponding points or surfaces of these two views 
are projected horizontally. The straightedge, as placed in Fig. 21, 
illustrates a horizontal projection. 



29 



POINTS OR SURFACES PROJECTED VERTICALLY. 

Whenever two views are placed above or below one another, 
all points or surfaces are projected vertically. Fig. 22 illustrates 
this, the straightedge being placed vertically in projecting the sur- 
face e. 







■ 


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1 

1 






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1 






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, , 51. 1 




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Fig. 23 is similar to Fig. 19, except we have cut out another 
portion of this block — the lower left hand corner. Fig. 24 shows 
the working drawing views of this block. 

The full line d again corresponds with line d on front view, and 
represents the length of this surface. The dotted line f on side 
view corresponds with line f on front view but is shown dotted 
on the side view because it cannot be seen when looking at the 
right hand side of block. It must be remembered that all lines 
which can be seen when looking at front, side, top or bottom of 
object are always indicated by full lines and those that actually 
exist but cannot be seen are always indicated by dotted lines. 

30 




fiq-25 




' 8 



ri^-24 



Had the side vieAv been placed to the left of the front view instead 
of the right, line d would be shown as a dotted line and line f 
as a full line. 

Referring to the top view — lines e and g correspond with lines 
e and g on the front view and represent the length of these surfaces. 





















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31 



Fig. 25. The surface f is here shown projected from the front 
to the side view. It will be seen that this surface is a trifle below 
the bottom of the hole (see front view). Note the relative position 
on the side view — line f also being a trifle below the dotted line 
representing the hole. 




\ 




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FtGi'Et^ 



Fig. 26 illustrates the method of projecting the surface g from 
the front to the top view. 



ii2 



EXAMINATION 
LESSON 3 

1. Is it possible, by looking at Fig. 12, to know if the square hole 
shown in the right hand side is also in the left hand side? 

2. Fig. 16. (a) Which views show that the hole extends thru the 

full length of the block? 

(b) By what kind of lines is this hole shown? 

(c) Why is this kind of line used? 

3. Fig. 20. (a) Which views show the length of the surface d ? 

. (b) Why is the line d in the side view B shown 
as a full line? 

4. Fig. 21. (a) Is the vertical height of the surface e shown in 

the side view? (Views named as in Fig. 16.) 
(b) Is it shown in the top view? 

5. Fig. 26. Why is line g dotted in the top view? 




33 



LESSON FOUR 



CROSS SECTIONAL VIEW (HOW PRODUCED). 

Let us imagine this block of wood has been cut in two as shown 
in Fig-. 27 — one part marked A and the other B. Take these two 
halves and set them together to represent a front view as shown 
in Fig. 28. Now imagine that part B is removed and by looking 




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4 


1 






< 








i 








\ 








s 








1 






II 


1 






Cff055 ^ECpON 



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W///Ma 




-mr/r/, 



s^ECTlON-CC 




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n^'JO 



at the side of part A it will appear as shown at the right and 
marked "section CC." The two parallel lines representing the 
hole are now shoA\Ti as full lines as the imaginary cut thru this 

35 



block will reveal this hole. The surfaces above and below this 
hole, or the surfaces which have been imaginarily cut, are shown 
covered with diagonal lines called ^ * crosshatching. " 

The notation section CC indicates that the imaginary cut has 
been taken along the line marked CC on the front view. 

It must always be remembered when crosshatching appears on 
a drawing that an imaginary cut has been taken thru a certain 
section of the object, the surfaces cut being crosshatched. 

Fig. 29 is a representation of the same block of wood (Fig. 23) 
except that we have shown the upper left hand corner rounded off 
one-half the length of the block. 

In Fig. 30 we have shown the working drawing of this block. 

REARRANGEMENT OF VIEWS. 

No doubt you will notice that the views in Fig. 30 have been 
rearranged when compared with those previously shown. It is 
immaterial which side view is shown — either right or left — but 
right hand views are shown to right of front and left hand views 
to left of front; likcAvise a top view is always shown on top and 
a bottom view at the bottom. 

On Fig. 30 we have also shown all dimensions necessary to ex- 
plain the details of this object. An explanation of the y^' R. and 
the I/2" dia. Avill appear later. Your attention is called to the 
placing of these dimensions and that wherever possible the dimen- 
sions are taken from the center lines. 



PROJECTIONS OF CIRCULAR OBJECTS. 




7v<^-3/ 





ffrONT 



S/oe 



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Fig. 31 is a representation of a round box having a hinged cover. 

Fig. 32 shoAvs this box with a flat disc or cover opened, and in 
opening it Ave have supposed that the cover has been held stationary 
and the box swung one-quarter way round, so that only the side 
is shown. This illustrates the projection of a circular object. 

36 



Fig. 33 has the hinge removed and the side view separated from 
the front. 

The object of the illustrations shown in Figs. 31, 32 and 33 
is to show the method of projecting the side view in relation to 
the front and by referring to Fig. 13 you will see that the method 
of projecting these views is exactly the same. 

You will note that at the top of Fig. 33 we have shown a top 
view also — in appearance it is exactly the same as the side, giving 
no further information other than shown in the side view, and for 
that reason top view might have been omitted. 

Fig. 33. It must be remembered that all depressed surfaces of 
the side of this box are brought to the same plane to produce the 
side view. Each point is projected horizontally. 



Fig. 34 shows a round disc with a hole thru its center. 



m^ 




ric,-54 




//^/c? -J5 



Fig. 35 shows this same disc in front and side views. Let us 
imagine we have taken a very thin slice from the face of the disc, 
opened and fastened it with a hinge, to the disc proper. We have 
shaded the upper and lower portion of this side view so as to in- 
dicate that it is round; however, this line shading seldom appears 
on a working drawing. A top view would be identically the same 




/v(?-v56 



n<^-^7 



^HO& 




37 



as the side, except that it would be placed above the front view. 
In this case a top view is not necessary. The removal of the hinge 
and separating the two views will produce working drawing views 
of this disc. 

Fig. 36. By comparing this perspective with Fig. 34, you will 
see that we have a disc with an extension on each side which we 
will designate as a hub; a hole is also shown thru the full length 
of the hub. 

Fig. 37 shows this disc with its proper projection. As you will 
note, the horizontal lines marked 1, 2, 3, 4, 5, and 6 indicate the 
various points which have been projected from one view to an- 
other, for example — 

Lines 2 and 5 indicate the outside diameter of the hub ; 
Lines 3 and 4 indicate the vertical diameter of the hole ; 
Lines 1 and 6 indicate the outside diameter of the disc. 
Again, a top view would be identically the same as side view. 

(By making a systematic analysis of each point or surface from 
one view to another as above explained, the reading of complicated 
working drawings becomes simplified.) Use a straightedge as ex- 
plained for Figs. 25 and 26. 




r/^-v3<5 



/P/A7 




H(/Q 



Fig. 38. Let us assume that to Fig. 36 we have added an ex- 
tension on each side of the disc around its circumference and we 
will designate this as the rim. 

Fig. 39. This is similar to Fig. 37. By looking at the side view, 
it is supposed that we are looking at the outside of the wheel. 
The horizontal lines 1 and 2, also 7 and 8, indicate the projection 



38 



of the thickness of the rim. We will explain the reason for the 
vertical dotted lines marked a and b which represent the thickness 
of the web. — The rim being wider than the web will cover the web 
completely when looking at the width of the rim. The distance 
between lines c and d represents the Avidth of the rim. The vertical 
lines a and b are dotted the full length to represent that the web 
extends all around the hub. The distance between lines e and f 
represents the length of the hub. 




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Fig. 40 represents a cross sectional view. By referring to Fig. 
27 you will readily understand that the wheel has been imaginarily 
cut along the vertical line AA (see front view). By removing 
(imaginarily) right hand portion and by looking towards the sur- 
face of the remaining portion, you will see a view shown at the 
right and marked section AA, remembering that the surfaces which 
have been imaginarily cut are covered with diagonal lines, called 
crosshatching. The general outline of the rim, web and hub is now 
shown by full lines instead of dotted as this (imaginary cut with 
one-half removed) will show a full outline when looking against 
the surfaces cut along line AA. 



General— The notation "section AA." or ''section A, B, C, D" 
(or any other combination of letters) indicates that an imaginary 
cut has been taken thru the object and the location of this cut 
is found by referring to one of the views and locating the above 
mentioned letters. 



39 




/7<5-4/ 



F/G-4-1 



Side View 



End View 



Fig. 41. Imagine that we have cut out a portion of the web 
shown in Fig. 38 and that sufficient of it remains to form spokes 
or arms — you will readily understand that Fig. 41 is a represen- 
tation of a wheel having spokes, hub and rim — the spokes taking 
the place of the web. 

Fig. 42 shows working drawing views of this wheel. The views 
of some drawings may be shown half in cross section; and the 
other half in full. In this case we have shown the upper half of end 
view in cross section and have assumed that the upper right hand 
quarter of the wheel has been removed (see side view). By looking 
at the end of the wheel, the upper half will have the outline of the 
rim, hub and arm or spoke shown in full, and the lower half will 
have the above mentioned shown dotted. 

Note that the line CCC indicates the imaginary cut and happens 
to pass thru the full length of one of the spokes, but as it is cus- 
tomary not to Crosshatch arms or spokes, it has not been done 
here, but strictly speaking, it should have been crosshatched as 
it has been cut by the line CCC. 



40 




EXAMINATION 
LESSON 4 

1. What does erosshatching on a drawing indicate? 

2. Fig. 28. (a) Is the lower left hand cut-out portion in part A 

indicated on the sectional view CC? 

♦ 
(b) Why is the upper right hand cut-out portion in part 
B not shown in the cross sectional view? 

3. What do the light lines indicate in the top and side views of 

Fig. 33? 

4. Fig. 37. (a) Which view shows the length of the hub? (Name 

view as in Fig. 33.) 

(b) Which view shows the thickness of the disc? 




41 



LESSON FIVE 



WORKING DRAWING VIEWS OF TWO SEPARATE OBJECTS 

COIOINED. 

Fig. 43. By referring to Figs. 34 and 19 you will see that there 
is a similarity. We have now combined two formerly separate 
objects and the working drawing views are shown in Fig. 44. 

By employing the same manner of projecting as has been ex- 
plained for an individual object, you will see that by combining 
these two, the horizontal lines 1, 2, 3, 4, 5, and 6 indicate the cor- 
responding points of the side and front views, and the vertical 
lines 7 thru 14, indicate the corresponding points of the top and 
front views. 




n^- 43 




p^-44 



Line 14 shows the extreme lower right hand point of the front 
view, projected to the top view. 

Attention is called to the projection of the surface marked a 
on front view, to the top view. Part of this line is shown dotted 
and part in full (see top view). The part of line directly under 
the roller is shown dotted as it is not visible, and the short distance 
this line extends beyond the rear of roller is shown as a full line 
as it can be seen when looking directly down on top of the object. 

43 



The roller does not extend the full length of the block and there- 
fore the line representing the surface beyond roller is visible and 
shown as a full line. 

Note — Take one line or surface at a time and project same (or 
find its corresponding line or point) on one of the other views. 
By taking one at a time it will enable you to readily understand 
the drawing. 



7^ 



i„2T/^IGHTeOGai 



//^^^/'**Z 




/': 



.-'/'. 



3 TRPlQ-HTEDG^i 



3TRRIGMTEDGE: 



Pig. 45 is an exact duplicate of Fig. 44 except that we have 
shown the projection of several points and lines from the front to 
the side view by the use of a straightedge. Starting at the top 
each line or point should be taken separately and projected. In 

44 



Fig. 45 we have only shown three different projections by the use 
of a straightedge, namely the top of roller, bottom of roller which 
also happens to be the top of the' block— the third surface pro- 
jected being the bottom of the block. 




/7c? - 4-^ 

Fig. 46. This figure illustrates the projection of the surface 
a Avith the use of the straightedge. The extreme left hand edge of 
the roller is also shown projected to the top view. Note the relative 
position of this edge of roller to the left hand edge of the block 
(front view). Look at the top view and note the relative position 
there. 



45 



In studying a working drawing it is good practice to note the 
relative position of the various lines as explained. This will also 
enable you to more readily locate the various points and lines 
without the use of a straightedge. 

PERSPECTIVE VIEWS NOT SHOWN ON WORKING 

DRAWINGS. 

Up to this point you had a perspective drawing to look at to 
assist in the understanding of a working drawing. However, in 
actual practice, there are no perspective dra^vings to illustrate 
the object and you must form in your own mind, the perspective 
view from the working drawing. 

For an example, a working drawing outline is shown in Fig. 
47. You are requested to make a free hand sketch showing the 
perspective view of this object. After making your sketch turn 
to page 50, Figs. 48 or 49, and check its correctness. 





r'<^-47 



DESCEIFTION OF GEOMSTEICAL FIGURES AND SOLIDS. 

A few of the commonly used figures and solids, each being 
properly named, are shown on page 47. Some of the terms are used 
thruout the lessons. 

Parallelograjn — A flat surface enclosed by four lines, opposite 
lines being parallel. (Squares and rectangles are parallelograms.) 

Square — A parallelogram having four sides of equal length and 
four right angles. AVhenever two lines meet, so that the angle is the 
same on either side, they form right angles, thus — ' — An 
ordinary carpenter's square is a good example of a right angle. 

Rectangle — A parallelogram having four sides, two of which 
are longer than the others and forming a right angle at each corner. 

Circle — A flat surface enclosed by a line which is the same dis- 
tance to all points from a common center. A circle may also mean 



46 




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^EiN\l'C/RCLE. 




Tf^mNGLE 









/ 


/ 


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Cyl /NO£ff, 




prnffM/o 



a curved line having neither beginning nor end and all points on 
the curved line being an equal distance from a common point within. 

Semi-circle — One half of a full circle. 

Triangle — ^A flat surface enclosed by three lines. When all lines 
are the same length it is known as an equilateral triangle. 

Right angle triangle — A flat surface enclosed by three lines, 
two of which form a right angle at their junction. 

Cube — A solid having six equal square sides. 

Prism — A solid, the ends being alike and all sides rectangular. 

Sphere or ball — A solid, all points of its surface being*an equal 
distance from a point within, called the center. 

Cylinder — ^A volume formed by a complete revolution of a 
rectangle about one of its sides as an axis. 

Cone — A solid having a circle for its base, and its lateral sur- 
faces uniformly tapering to a common point, called the vertex. 

Pyramid — A solid having any number of sides for its base and 
the lateral surfaces triangular, the apex of each meeting at a com- 
mon point called the vertex. 

DESCRIPTION OF INSTRUMENTS AND TOOLS. 

Page 49 illustrates the most common tools used by a draftsman 
in making working drawings. They are shown to give a general 
knowledge of their construction, use and proper name. 

The illustration at the top is known as a T square, getting its 
name from its general shape. It consists of a short piece known 
as the head, which is fastened to the thin, straight edge, known as 
the blade. T squares are usually made of wood. The inner edge 
of the head is designed to fit the left hand edge of the drawing 
board. When used, it is held securely against this edge with the 
left hand, while the right draws the horizontal line along the upper 
edge of the blade. When a horizontal line is desired at any other 
position, the T square is moved either up or down, keeping the 
head firmly against the left hand edge of the board until the 
desired position is obtained. 

TRIANGLES. 

The commonly used triangles are shown and marked **45° tri- 
angle" — ''30-60° triangle." They are made either of wood or 
celluloid. 

The 45° triangle has two 45° angles and one 90° angle. 

The 30-60° triangle has one angle of 30°, one of 60° and the 
third of 90°. 

48 



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o 

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49 



A drawing board showing the T square and triangles in position 
is shown in the center. 

The series of diagonal lines shown above the triangles were pro- 
duced by drawing a line along the diagonal edge of the triangle, 
then moving the triangle horizontally a short distance toward the 
center of the board, and drawing another line along the upper edge 

of the triangle. 

A compass is shown in the lower left hand corner. This instru- 
ment is used to draw circles, or arcs of a circle, either with pencil 
or ink. The lower ends of the legs may be removed and the pen may 
be inserted when desired; when a very large radius is desired, the 
extension bar may be inserted. One end of this extension bar has 
a socket to accommodate either the pen or pencil. This bar is shown 
between the compass and pen. 

. A divider is similar in construction to a compass, having remov- 
able points. This instrument is used to lay off distances, either 
from a scale or some other part of the drawing. 

Other instruments used are known as bow pencil, bow pen and 
bow divider. They are used similarly to the compass and divider, 
except for smaller circles, arcs, etc. These instruments have no 
removable legs. The bow pen, pencil and divider are separate in- 
struments. The distance between the points is regulated by turning 
a thumb nut. 

A ruling pen is similar in construction to the pen shown with 
the compass except that it is provided with a short handle. 

Ink is fed between the two blades of the pen, from a quill which 
projects from the under side of the cork in the ink bottle and into 
the ink. The thickness of line is regulated by adjusting the thumb 
screw near the points of the pen. 

Special ink, known as India Ink, is used. 





pCf' 4S Off p^ "49, 

50 



EXAMINATION 
LESSON 5 

1. Are the lines representing the rear of the cylinder and also of 
the block shown in both side and top views in Fig. 44? 

2. Make working drawing views of the prism and cylinder shown 
on page 47. . 

3. (a) Give definition of a cone. 

(b) Give definition of a sphere. 

(c) Give definition of a right angle triangle. 

4. (a) Name the angles in the 45° triangle, 
(b) Name the angles in the 30-60° triangle. 

5. (a) How are horizontal lines drawn when using a T square? 
(b) How are vertical lines drawn when using a T square and 

triangle? 




51 



LESSON SIX 



The fundamental principles of projections have been discussed 
and it is of utmost importance that you clearly understand the 
work covered. We advise you to study Lessons 1 to 5 — going over 
the entire work several times and as you proceed with the instruc- 
tions — review the previous lessons. 

The following lessons cover important points which are essential 
to the reading of complicated working drawings. 

The notations on page 54 should be carefully studied. Thru- 
out the lessons, notations Avill appear and you should be able to 
readily interpret their meanings. 

Review the following important rules which must be observed 
in the reading of working drawings : 

1. The line of vision must be in a direct horizontal line with 
all points along its height, length or width for horizontal 
projections; and in a direct vertical line with all points 
along its length and width for vertical projections. (See 
page 20.) 

2. All depressions and extensions must be brought to the 
same plane. (See page 20; also illustrated in lesson 8.) 

3. Each view represents that which can be seen when look- 
ing directly at the object, with a view representing only 
one of its faces — a side, an end, the top or bottom 
visible at a time. 

4. No single view will give all the information necessary to 
explain the object (except very simple objects), there- 
fore two or more views of an object must always be 
studied. 



EXPLANATION OF NOTATIONS APPEARING ON WORKING 

DRAWINGS. 

This f sign indicates that a surface is to be finished or machined 
— it may also be shown thus: — F. 

53 



This sign )C should be placed thus -f- 



The short diagonal line of the sign should intersect the surface 
line which is to be finished or machined. 

Diameter (dia) is the distance across a circle at its widest point 
and is indicated thus : 



Q 



5, OR 

1_ 




Radius (R or Rad) is one-half the diameter of a circle — or may 
be indicated in a corner connecting two lines: 



© i^ 



€- 



Circumference is the distance around the outer edge of a circle. 

These notations relate to 



P. D. pitch diameter 
0. D. outside diameter 
D. P. diametrical pitch 
C. P. circular pitch 



dimensions for gear teeth 



Press Fit: — Two parts fitted or machined so as to require pres- 
sure to force one over the other and sufficiently tight so as not 
to move or rotate. 

Running Fit: — Two cylindrical parts sufficiently loose so that 
they will be free to rotate. 

Drive Fit: — Two cylindrical parts machined — the inner part a 
trifie larger so that when assembled with its component parts, they 
are sufficiently tight to require a driving force to bring them to- 
gether. 

Shrinkage Fit: — Two parts machined, the outer just a trifle 
smaller, which, when heated expands and passes over other part. 
In cooling, this part will shrink sufficiently to produce a very 
tight fit. 

Bore: — A hole bored with a machine tool (drill press, lathe or 
boring bar). 

Drill: — A hole drilled with a machine tool (drill press). 

Ream: — Enlarging a hole with a reamer after being bored or 
drilled (hand, drill press or lathe). 

Cored Hole: — ^A hole in a casting produced by pouring the 
liquid metal around a sand core placed in a mold. 

54 



Face: — The width of a gear or pulley; or may mdicate a ma- 
chme operation — that of cutting off part of the surface with a 
machine tool (lathe or boring mill). 

Turn: — Taking a cut off the circumference in a lathe or other 
machine tool. 

Broach: — A machine operation — that of enlarging a previously 
made hole to some special shape by forcing a drift thru it. 

Grind: — The operation of grinding off a portion of the surface 
with an emery wheel or surface grinder. 

R. H.— Right hand. 

L. H. — Left hand. 

dz Indicates allowable variation from a decimal dimension. 
To illustrate their use ; — ^if written thus^ 5.000" ± .001", it would 
indicate that the finished dimension may be .001" larger or smaller 
than 5.000" and will be accepted as being machined correctly. 

.001" is read ''one thousandth of an inch" — less than the thick- 
ness of a hair and is measured with an instrument known as a 
micrometer, which is illustrated. 





A— Frame 

B-AnvU 

C— Spindle or Screw 

D- Sleeve or Barrel 

E- Thimble 



—Micrometer. 



C. I. — cast iron 

I. — ^iron 

St. — steel 

C. St. — cast steel 

W. I. — wrot iron 

Brs. — brass 

Cop. - — copper 

Alu. — aluminum 

C. Brs. — brass casting 

C. R. S. — cold rolled steel 

0. H. S. — open hearth steel 

Semi-St. — semi-steel 



Forg. 
M. S. 
T. S. - 

Ec. S. ■ 
C. Bore- 
P. Tap - 
Ctrs. - 
Thds. - 
Bush. - 
Tap - 
F. A. 0. 



4 



-forging 

-machinery steel 

-tool steel 

-electric steel 

-counter bore 

-pipe tap 

-centers 

-threads 

-bushing 

-tap 

-finish all over 

-center line 



55 



S. F. — Spot face — a machine operation (generally drill press) — 
that of cleaning up the rough surface of casting which will come 
directly under the head of a bolt or nut. 



B. C— Bolt circle. 



SCALES. 




Fig. 50 

All drawings cannot be made full size as space will not permit, 
therefore all parts are reduced proportionately by the use of a 
reducing scale. Fig. 50 illustrates one form of reducing scale. As 
you will note, it is triangular in shape and is generally about 12" 
in length. It has six edges on which are marked eleven different 
scales. The full size scale covers one entire edge — all others are 
grouped in pairs, for example; — the 3" scale at B and the IV2" 
scale at the other end marked A. The 3" scale indicates that a 
length of 3" is divided into twelve equal spaces representing inches 
— each in its turn subdivided into parts of an inch. It will be seen 
that by using this scale an object may be reduced to one-quarter 
its actual size as 3" equals % of 12. 

The ''IV2'' equals 1 foot" scale is used when it is desired to 
reduce an object % its actual size, as 1% is Vs of 12. The scales 
on the edges are grouped as follows: 

At one end At other end 

yo"=l' 1"==1' 

yl =1' 1/8"=!' 

_3_", 1' 3 " 1' 

16 ' -^ 3 2^ J- 

3"=1' 11/2"==!' 

12"=-!' 

Whenever drawings are made without dimensions, the scale to 
which the drawing is made is generally noted on the drawing. By 
scaling the various distances using the scale as noted, the dimen- 
sions may be determined. In some instances a dimension may be 
shown which, when scaled, does not check with the dimension — 
in such a case the dimension shown is ahvays considered correct. 

Some drawings are marked ''Not to scale" or "Do not scale." 
—In that event only the dimensions shown should be used. Draw- 
ings with the above notations usually have some parts which are 
not drawn to scale or have had some changes made in the dimen- 
sions of some of the parts without changing the drawing to scale; 
or it is desired that the mechanic work to the dimensions given 
instead of determining any of. the dimensions by the use of a scale. 

50 



Some scales are divided into 1/10, 1/20, 1/30, etc. parts of an 
inch. These are generally used by architects and civil engineers. 

In making a drawing V2 actual size, the full size scale is used, 
and each dimension reduced accordingly by one-half. For exam- 
ple, a dimension 9%" long is made 4V2" plns %" equals 4%" in 
length when made half size using the full size scale. 

CROSS SECTIONS AND CROSSHATCHING. 

The surface of a cross sectional view which has been imaginarily 
cut is always covered A^dth a group of lines (generally diagonal) to 
form symbols used to designate various materials. 

The grouping of these diagonal lines is known as crosshatching 
and is employed to illustrate that a certain section or imaginary 
cut has been taken at some position in the object and the symbol 
indicates the material from which the object is made. The con- 
ventional forms of crosshatching as adopted are shown. 

Conventional Torm5 o/^ Cro35 5EcpoN/N(^. 




C/i^f IffoN 





Z.INC 




///S(/ijfr/oN 







W>?or fffotf. fi^lnLLEfiBLe l. 



3fr/t33 






C/isr3r££L. W/roT-3nEL alloy sjitL. CofFER. 






3/J3dirT- fliUMihJUM. CoMPos/r/o^ 






L/QUfO 



(^l/fS3 



£/f/rTH 



4 . ^ / a ^ 





'^^ND. 



CoNCffET^' 



3fficn 



W^oo. 



57 



However, the practice of indicating the various Diaterials with their 
corresponding symbols is not always followed and a deviation from 
these illustrations will be met with. 

In making working drawings, it is also customary that the mate- 
rial is noted on the drawing or on a specification and this should 
always be the guide in determining the material which is to be 
used. Additional symbols representing materials not shown here 
may be used. 



Conventional Form^ or 
Representing, 3REfin>^. 




.30L/D CYL/HDER - C/fSr //TON. 




/Follow Cylinder, c/isr sn^L 





'fJM3£R, 



Wooo. 




X>^R ^JOCn- W/ftj;- Iron. 



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aSEfe» 




. 4c''o^ ^ 



.57: 



58 



Page 58 shows the conventional forms of representing breaks 
and also the method of indicating the broken portion, which is 
shown crosshatched to correspond to the material as listed under 
each item, as for example solid cylinder cast iron. This has the 
single, evenly-spaced diagonal line covering the broken portion, 
indicating cast iron. Breaks are employed whenever it is impossi- 
ble to conveniently show the full length or height of an object and 
a dimension placed from one extremity to the other indicates its 
total length. The 40' 0" dimension from one extremity to the other 
on the structural steel beam illustrates the above. 

A piece may be sho^^ni broken and have several dimensions indi- 
cated for its length. This would show that several pieces are to be 
made to the various lengths. 



EXAMINATION 
LESSON 6 

1. (a) What is the diameter of a circle? 

(b) What is the circumference of a circle? 

(c) What is a cored hole? 

2. What do the following abbreviations represent? 

M.S. 
C. R. S. 
W. I. 
0. H. S. 

3. If you wish to make a dramng J^ of its actual size, what scale 
would you use? 

4. In the event a part of drawing was crosshatched to represent 
cast iron and a notation specifies that the material is to be made 
of brass, which would you use ? 

5. Why are breaks, as shown on page 58, used? 



58 



LESSON SEVEN 



METHOD OF INDICATING CROSS SECTIONS. 

Lesson 4, Figs. 40 and 42, illustrate the method of producing a 
cross sectional view. Fig. 40 is a full cross section and Fig. 42 a 
half cross section. Fig. 51 illustrates another method of shomng 
the form of construction thruout the length of an object, the handle 
(or upper portion) being round. Directly below this is a length 
which is square and below this it is rectangular. The long dash 
line passing thru the cross sections also designates the position 
where these cross sectional views were taken on the object. 





//<5- 5/ 



p^-52 



61 



Fig. 72 also illustrates the foregoing. 

Fig. 52. It is the usual practice when a cross section is taken 
thru a connection as here illustrated, to alternate the direction of 
the diagonal lines. The lines, where the change of direction takes 
place, indicate the surface of an adjacent part, also the cross 
hatched surfaces of the same piece have the diagonal lines in the 
same direction. To illustrate, part A is one piece and part B the 
other. Both ends of the fork part B have the diagonal lines in 
the same direction. 




Fi(^- 63 




Another method of indicating the cross section of a certain 
part of an object is to place it directly within the outline of the 
object as illustrated in Fig. 53. This represents a bar of iron being 
round for about half its length and the other half square. 

ZIGZAG CROSS SECTION 

By employing the zigzag line to locate cross sectional'views, it 
is possible to show the complicated parts of an object more clearly. 
In Fig. 54 is shown a square block having an oblong tapered hole 
in the upper right hand — a round projection with a hole thru 
its center in the lower left hand corner — the lines A, B, C, and D, 
one letter appearing at each offset. In this figure only one zigzag 
or offset is shown. However, some drawings may have two or 
more, the zigzag line always indicating the imaginary cut, the 
cross sectional view revealing the surfaces cut and covered with 
crosshatching to represent the material from which it is made. 



G2 




n<^- ^4 




HALF AND QUARTER CROSS SECTIONS. 

Fig. 55 shows a perspective view of a cube, and it is assumed 
that we have cut out one portion and marked it c — cut out an- 
other and marked it d. The c and d portions have been removed 
from the cube proper and set to one side as shown. 



^ 




r/^'^5 t. 




Mm F 3£cjion ON LiN£ One Ou^nren 3£C. 



ON Lif^E hh 



63 



By referring to the working drawing views, placed at the right 
and marked Fig. 56, it will be seen that the lines aa and bb indicate 
the corresponding center' lines in both perspective and Avorking 
drawing views. 

Referring to Fig. 55 let us assume that we have replaced the 
block marked d in its proper position in the cube. By looking 
against the surfaces which have been imaginarily cut by the re- 
moval of block c, a side view is obtained as shown and marked 
"half section on line aa," (see Fig. 56) indicating that the half 
section is taken on line aa, the full height of the cube. 

Let us assume that block c is replaced and block . d removed 
from the cube proper on the perspective view. Then by looking at 
the end, a view is obtained and marked ''one quarter section" on 
line bb. See working drawing views. 

It is important to remember that these cuts are imaginary and 
that a cross section shown on one view has no relation to the one on 
another view. This was illustrated in the two working drawing- 
views (side and end) and is the result of imaginarily replacing 
block c and d in the cube proper. 

BOLTS, THREADS AND TAPS. 

Various methods of representing bolts, threads and taps are 
here illustrated. Fig. 57 shows the general method of indicating 
threads, being alternate light and heavy horizontal lines. Fig. 58 
shows another method — it being alternate light and heavy diagonal 
lines sloping from the left to the right, indicating that these are 
right hand threads. 

Fig. 60 is similar to Fig. 58 except that the diagonal lines slope 
from the right to the left, indicating that these are left hand 
threads. Fig. 59 represents a method of indicating threads gener- 
ally used on tool drawings. 

When threads are shown as in Fig. 57 or Fig. 59, it is always 
uliderstood that they are right hand, unless otherwise marked. 

Fig. 61 shows a cross sectional view of tapped hole, the bottom 
of which shows the point of the drill. Attention is called to the 
various methods of indicating the end view of these tapped holes. 

Fig. 61 shows a complete circle with a larger circle circum- 
scribed % around. 

Fig. 62 shows another method of indicating the end view of a 
tapped hole — it being a % circle inscribed in a complete circle. 

Fig. 63 shows still another method of indicating the end view 
of a tapped hole — it being a 14 circle circumscribed around a com- 
plete circle. 

64 



Fig. 64 shoAvs the method of projecting tapped hole when it is 
projected from an angle. 




SHRINK RULE— EXPLANATION AND USE. 

Shrink rules are special rules used by the pattern maker. It has 
been found that as castings cool after being poured, the amount of 
shrinkage varies when made of different materials. In order to 
take care of this shrinkage or contraction of the metal so that the 
finished product will be of the proper pre-deterrrined size, the pat- 
tern must be made larger than the finished casting. It is evident 
that if it were made the same size as the finished casting, it would 
be smaller than desired, therefore a shiink rule which will take 
care of this shrinkage is employed by the pattern maker. This rule 
is a trifle longer than the standard — the length depending upon 
the shrinkage of the different materials. 

Before the pattern maker starts work on his pattern he is in- 
formed as to the material of which it is to be cast, and will use the 
proper shrink rule to produce the required amount of shrinkage. 

G5 



If casting is to be made of steel, the rule will be 1/4" longer 
than the standard foot, indicating that steel in cooling will shrink 
%" for each foot of its length. 

Brass will shrink jV' foi" each foot of its length. 

Cast iron shrinks %" per foot. 

When making patterns of great length, a slight deviation from 
the above is resorted to. 

Let us assume the pattern maker is to make a pattern — the cast- 
ing made from same to be cast iron. He will use a rule which, by 
actual measurement, is made 12ys" in length and divided into 12 
equal parts, which in turn are subdivided to the various fractions 
of one inch. It ^\ill be seen that each inch in length will be a trifle 
longer than the standard inch. With this rule the pattern maker 
works to the dimensions given on the drawing, using the particular 
shrink rule for cast iron and when the casting is finished, it will 
shrink sufficiently to have the dimensions desired. 

THE MEASUREMENT OF ANGLES. 

In the mechanical world angles are measured by degrees or sub- 
divisions of a degree. For such measurement the circumference of 
a circle is supposed to be di^dded into 360 equal parts, and the 
angle formed by drawing a line from two adjacent points of the 
circumference to the center is an angle of one degree, and is writ- 
ten thus, 1°. The small circle above and to the right is the symbol 
for degree. Fig. 65A illustrates an angle of 1° to a slightly en- 
larged scale. The distance betAveen the two lines at the circum- 
ference represents 1/360 part of the circumference. 

If we were to add up ninety of these divisions and draw a line 
between the first and the last one to the center, the angle formed 
Avould be 90° or the l^ part of a complete circle. The upper half 
of Fig. 65B shows two angles of 90° each. 

The lower half of Fig. 65B shows the half circle divided into 

four equal parts, each being marked 45° (or i/2 of 90°). If the 

complete circle (360°) were divided into eight equal parts, each 
Avould contain 45°, as 360-^8 equals 45. 






66 



The upper half of Fig. 65C is shown divided into three equal 
parts, each marked 60°, as the half circle contains 180°, which, 
when divided into three equal parts, equals 60 (180^H-3=60). Divid- 
ing one of the 60° spaces equally in two will make each angle 30°. 

If the complete circle is divided into three equal parts, each 
will contain 120° (360^3=-120). See Fig. 65D. 

The above divisions are the most common^ altho any number of 
degrees or fractions of a degree may be used. 

For accurate measurement a degree may be subdivided into 
60 equal parts, called minutes, each of these again in turn, being 
subdivided into 60 equal parts, called seconds ; hence the following 
notation on a drawing 

61° — 32' — 15" 

is read ''sixty-one degrees, thirty-two minutes and fifteen seconds." 




Protractor 

Degrees and minutes are laid out with a special instrument known 
as a protractor — an illustration of which is shown. However, it 
is not always possible to read this instrument closer than wdthin 
five minutes, and it is very seldom that any tradesman except a 
machinist, tool-maker or pattern maker will be called upon to make 
layouts using other than those most common. 



CHAPLET. 

Fig. 66 is a perspective view of a chaplet. A chaplet is made 
of a very fusible metal and used to support a core when placed 
in a mold. The liquid metal when poured into the mold, readily 
melts the chaplet. 

67 



Fig, 67 represents working drawing views of this chaplet. It 
Avill be seen that the two flat discs are shown as a large and smaller 
full outlined circle in the end view, and the stem is shown in this 




/y<^''CC> 




/7<^-^7 



same view as the small dotted circle in the center. It is dotted as 
it exists but cannot be seen when looking directly at the end of 
the object. 

The light lines between the two views are known as Construc- 
tion lines. These lines are never sho^v^i oh a working drawing, but 
are used in this case to assist in locating the corresponding points 
or surfaces on the two view^s. 



68 



^^ 



EXAMINATION 
LESSON 7 

1. What material does the crosshatehing in Figs. 51 and 52 rep- 
resent? 

2. Do Figs. 57 and 58 indicate the same kind of thread? 

3. (a) If a complete circle were divided into twelve equal parts, 
what is the angle between each part? 

(b) If it were divided into 90 equal parts, what is the angle 
between each? 

4. Which view in Fig. 54 shows the thickness of the block proper? 

5. Why is the inside circle dotted in Fig. 67? 




69 



LESSON EIGHT 



ANOTHER METHOD ILLUSTRATED OF BRINGING ALL EX- 
TENSIONS AND DEPRESSIONS TO THE SAME PLANE. 







:ojL 



Top ^/£\fJ 



€U 




k 




|i M 11 1 1 r 



i''""' -j 




I I . • 1 1 > I 



71 



Thickness or <kLfi^^ 

-CL. 




I i l l I II 11 



Jv(Sf'63. 



Fig. 68. Let us suppose that between the top and side view we 
have placed a sheet of glass and that you are looking against its 
edge so that only the thickness will be seen. 

Now let us take an ordinary carpenter's square and hold the 
short leg of it against the underside of the glass plate and the long 
leg against the extreme left hand edge of the shovel. With the 
square held in this position move it back and forth along this edge. 
If a line were drawn on the glass at the points where the longer 
leg of square meets it and were you to look down thru the glass, 
a line as shoAvn on top view and marked a b would be produced. 
Now if the square, held in this position, were moved all around the 
shovel with the long leg just touching, and each point marked on 
the glass plate an outline of the shovel would be seen when looking 
down on the glass. This illustrates another method of bringing 
all depressions and extensions to the same plane, the glass plate 
being the plane in this case (see also Fig. 11 in Lesson Two). 

The projection of the cylinder which forms the handle is shown 
at the right, the two parallel lines in the top view being the lines 
projected. 

71 



SCREW DRIVER. 



^1 




§. 



f 

F/G,-G9 




J-O^ V/EW 



S>iOE. Vte. w 



Fig. 69 is a working drawing view of a screw driver and no 
doubt you will experience no difficulty in understanding the object 
— the handle is cylindrical and the opposite end flattened and tap- 
ered down. 

Looking directly at the screw driver with the flat surface to- 
ward you will produce a vieAV as shown at the top ; then by looking 
at the side so that the taper may be seen, an outline as marked 
''side view," will be produced. 

The handle is not shown in the side view as it is not necessary — 
the portion of side view as shown is all that is needed to clearly 
explain the end of the screw driver, the notation, ''DIA" as placed 
on the handle will explain that these parts are cylindrical. 

WRENCH. 




r'd'/o 



A special wrench is shown in Fig. 70, one end being known as 
an open end and the other as a spanner. This drawing illustrates 
the position of an angle projected view, the placing of a cross 
sectional view, the cast steel symbol of crosshatching, and the man- 
ner of projecting the various points from one view to the other. 

The angle projected view above the open end of wrench shows 
the thickness and width of jaw; however, this view does not show 
any other part of this wrench and is therefore classified as an 

72 



auxiliary view. The construction lines at the left hand end and 
placed between the top and side views show the various points 
projected. 

We advise you to project the points, lines or surfaces of the 
opposite end of the wrench in the same manner. 

An illustration of line shading is shown at A which assists 
in showing the enlargement at the end of the wrench. 

The placing of cross section view is explained on page 62. 



STANDARD ELBOW. 




Fig. 71 represents a working dra^dng outline of a standard pipe 
fitting (elbow). The method of indicating pipe threads is shown 
by dotted lines. It is customary to make no distinction in the thick- 
ness of lines representing the threads when dotted, however when 
threads are shown in full or in cross section, the alternate lines 
are heavy and light. See page 65. 

Study the projection of the various points with the use of the 
straightedge as explained in Lesson 3. 

If possible secure an elbow fitting and compare the actual 
article with this drawing — ^holding it in the positions here out- 
lined ; also look down at the elbow directly from the top and make 
a free hand sketch of the top view. — This will be very good prac- 
tice. 

73 



MALLET. 

Fig. 72 represents a working drawing outline of a wood mallet. 
Side and top views are shown. 




One method of indicating the shape of the handle is shown by 
the cross sectional views. The vertical lines passing thru these 
sections locate the positions of the various cross sections along the 
length of the handle. In some instances these cross sections are 
shown directlj^ on the outline of the object. (See page 62, Fig. 53.) 

Cross section indicates wood. 

The two circles in top view indicate that the mallet head is 
larger in diameter at its center than at the top and bottom. — The 
inside circle represents the top of mallet (side view) and the outer 
circle the diameter at the center, 

The dotted lines thru the mallet head indicate the hole, as well 
as the handle. The wedge in the end of handle is also shown 
dotted. 

The bottom diameter of mallet head (side view) is the same as 
the top ; if it were not the same, the top view would show another 
dotted circle indicating its diameter. HoAvever, none being shown, 

74 



it is correct to assume that the top and bottom are the same in 
diameter. Furthermore, if an attempt were made to show the bot- 
tom diameter of this mallet head in the top view, a dotted circle 
indicating its diameter would fall directly on the full inner circle, 
and therefore could not be seen. 

PERSPECTIVE DRAWINGS OF MOLDERS' TOOLS. 

On page 76 you will see various tools used by molders in the 
ramming and placing of sand in a mold — their use being common 
to the foundry molding trade. 

We have taken the second illustration shown at the top of the 
page, a hand rammer, and have made a working drawing of it. 
Fig. 73 illustrates the w^orking drawing of this hand rammer. It 
should be noticed that neither the side nor top view indicates that 
the right hand end of this rammer is cylindrical, therefore the end 
view has been added to explain this. 




jor Vi£w 



£N0 Vf£W 




-^IDS VjEW. 



n^ -7-3 

Sufficient views should always be used in connection with work- 
ing drawings to clearly show the outline of each and every part 
of the object. 

As mentioned the large full circle in the end view shows the 
construction of the right hand end (see top view). The two small 
dotted circles show the construction of the handle and the flat 
dotted oblong show^s that the left hand end (see top view) is flat. 

75 



Flool- and Hand Rammers 




Finishing Trowel 



Finishing Trowel 



Lifter 



Yankee 



Bench Lifter 




Finishing Trowel 




Square Trowel 




Slick and Spoon 



76 




EXAMINATION 
LESSON 8 

1. What notation on Fig. 69 explains that certain parts are cylin- 
drical ? 

2. What material is wrench in Fig. 70 to be made of? 

3. Why are the threads shown tapered in Fig. 71? 

4. Fig. 72 shows a side and top view. Would bottom view look 
the same as top view? 

5. What do the two dotted circles indicate in the end view of Fig. 
73? 




77 



LESSON NINE 



WOOD FLASK 
D 




Fl(k - 74 



Fig. 74 represents the perspective of a wood flask for use in a 
foundry for molding purposes. It is composed of a bottom board 
A, drag B and cope C. Cross bars are shown at D, the object of 
which is to support the sand while it is being rammed into the 
mold. This drawing is shown to give you a general knowledge 
of a perspective drawing and also to familiarize you with equip- 
ment used for foundry work. The working drawing of a similar 
flask will be shown and explained later. 



79 



IRON FLASK. 




ri(^- 75 



Fig. 75 shows a perspective drawing of a cast iron flask com- 
posed of a cope and drag. The cope and the drag are generally 
cast of cast iron, the trunnion A and ribs B forming part of the 
casting. The trunnion A forms a suitable fastening for crane 
hooks or chain and allows the cope or drag, as the ease may be, to 
be rolled over when desired. 

Your attention is called to the cast iron or cast steel cross bars 
shown at C. You will note these cross bars have numerous holes 
in them — the object of which is to further assist in supporting the 
sand after it is rammed in place. 



PERSPECTIVE AND WORKING DRAWING VIEWS OF A 

FOUNDRY FLASK. 



Fig. 76 shows a perspective view of a foundry flask. It con- 
sists of an open box made of wood — the two long sides having the 
ends cut doA^Ti to form handles. For the sake of an example and 
to illustrate the method of projecting, we have shown the rear 
board of this box approximately twice as thick as the front board. 



80 



Fig. 77 represents the working drawing views of Fig. 76. The 
lines A and B, also C and D, are shown dotted on the front 
view as they are hidden from actual vieAv when looking at the 
front of the flask. The lines B and C, also E and F indicate the 
inner surfaces of this box and the corresponding surfaces are 
sho^\ai Avith the same letters on the other views. The projection 




LnD V/£W 



r'^-77 



and relative position of the views are obtained in exactly the same 
manner as previously explained, and if you \n\\ refer to Fig. 68, 
bearing in mind the principle of bringing all depressions and exten- 
sions to the same plane,, you will be able to readily understand 
this drawing. The rear board of the flask, as mentioned, is approx- 
imately twice as thick as the front board. We will explain hoAv 
this thickness is shown on a working drawing : 



By referring to the top view, the inside of the rear wall is 
indicated by the letter E and the correct projection of this surface 
is indicated by the dotted line E on the end view. 



81 



Attention is called to the projection of the inside surface F on 
the end view. This board being the same thickness thruout its 
length, makes it impossible to indicate the inside surface of the 
box on the end view, as a dotted line would fall directly on top 
of the full line F on end view, and is therefore omitted. However, 
the thickness of the front board is shown on the top view. It is 
important that sufficient views and cross sectional views be shown 
to thoroly explain an object and if a surface or point is not pro- 
jected on one view, its position or outline may be seen by referring 
to one of the other views. The projection of the surface F illus- 
trates this point. — The light lines at the left indicate the corre- 
sponding lines between Fig. 76 and Fig. 77. 

SHANK. 




:=^ 



Jo/^ V/£W. 



< 



^ 



P^ 



3-H 



^(0£. \//£ W. 



-79 



Fig. 78 represents a perspective view of a shank for a bull 
ladle. When in use, a pot or ladle is inserted into the circular 
band, filled with molten metal and conveyed to the molds. 

The line shading is here shown on the band to illustrate its 
use. 

Fig. 79 shows a top and side view working drawing of the 
shank. Attention is called to the placing of views, construction 
and placing of center line, and the dotted line shown at A which 
indicates a point on the inside diameter of the band ; again, it must 
be remembered that when looking at the top view only a top view 
is seen; likewise when looking at the side, only the side is visible. 

82 



SINGLE VIEW DRAWING. 
TENSILE TEST BARS. 

Fig. 80 and Fig. 81 represent two different types of tensile 
test bars. 

A tensile test bar is machined to the dimension as showTi and 
made from material to be tested as to its tensile strength, reduc- 
tion of area and elastic limit. This bar is then placed in a testing 
machine, clamped between a jaw at the top and one at the bottom ; 
a pull is then exerted until it is ruptured, at which time a reading 
is taken. 

You will note that in each ease only one view is shown, but 
that sufficient dimensions and notations are given to indicate that 
these bars are cylindrical. 

The bar shown in Fig. 81 must be provided with a special jaw 
which screws onto the ends of the bar. 




Fig. 80 



/ " 




^ro T^iTZ^ 



Fig. 81 



83 



NUMBER OF VIEWS NECESSARY. 

Two or more views are employed to show the various details 
which make up the object. Whenever all the details can be clearly 
shown on one view, only one is necessary; this, however, applies 
only to very simple objects, such as solid cylinders, etc., when 
proper notations appear to explain more fully. 

No more views should be shoT^Ti than are necessary to clearly 
explain an object. If all details can be shown on two views, three 
or more would be superfluous. 

In some of these pages more views are shown than necessary, 
but this is done to illustrate various points. 



THREE VIEW DRAWINGS. 




O^/ofi Vjew 



E'NO ViEW. 



r'<^'Sz 



Fig. 82 represents the working drawing views of a shoe repair 
anvil. This is a good example of the necessity of having a three 
view drawing. 

The top view shows the outline of the anvil, representing the 
sole of a shoe, and the position of the ribs. (Ribs shown dotted.) 

The side view shows the shape of the rib a, position and shape 
of cross ribs b and c and general contour of the anvil. 

The end view shows the tapering side of ribs a and shape at 
under side of ribs b and c. 

84 



In completing the working draAving for this anvil it will be 
necessary to show several cross sectional views. Several of the 
points are projected from one view to the other by the use of 
either horizontal or vertical lines. 

Regardless of how these views are arranged, three will always 
be necessary. It is evident that the shape which represents the 
sole of the shoe (top view) cannot be shown on either of the other 
views and likewise the general shape of the anvil (side view) can- 
not be shown on either of the other views. 



^^ 



EXAMINATION 
LESSON 9 

1. Which views show that the rear wall of flask in Fig. 77 is 
thicker than the front? 

2. Is there sufficient information on Fig. 81 to indicate the shape 
of the portion which is marked 19/32 inch? 

3. In Fig. 82, which view could have been omitted? 



85 



LESSON TEN 



CHILL ROLLS. 

Chill rolls are used in rolling mills and are of various shapes, 
depending upon what is to be rolled. 

Fig. 83 represents a chill roll for rolling flat plates. A set, 
consisting of two, is placed one above the other, with just sufficient 
space between them, to allow for a thickness of the plate. The ingot 
which has previously been heated to almost the melting point, is 
then forced between these rollers. It requires severa,! sets of 
rollers to reduce the plate to the desired thickness. 

These rolls are usually cast solid, of a semi-steel chilling mix- 
ture and cast against a chill. This produces a very hard, close- 
grained surface on the outside of the roll. 





fic-85-fl 



Fig. 83 shows a side and end view of a chill roll. The construc- 
tion lines show the various points projected from one view to the 
other. 

87 



By referring to the end view, you will note the special shaped 
outline in the form of three legs — the length of these is indicated 
by D (side view). It will also be noticed that these three legs 
are enclosed with the circle marked C (end view) and the length 
of this shoulder is shown and marked C in the side view; like- 
wise the circle marked B represents the main portion of the roller 
— the length is indicated by the letter B in the side view. 

Fig. 83A is known as a wobbler coupling and is used to connect 
the ends of two rolls. It is cored out to the special shape shown 
and fits over the end of the roll Fig. 83. The dotted lines represent 
various points or surfaces of the cored hole, also that this hole 
extends thru the full length of coupling. 

BEARING BRACKET 




nc,-e4- 




^/DE v/tw 



EnO \Ji£-W. 



88 



Fig. 84 is a perspective drawing of a bearing bracket and Fig. 

85 shows this bearing bracket in working drawing vie^\'s. Compare 
Fig. 44 with this figure and you will see that the upper portion of 
the side view is similar to Fig. 44, and the upper portion of the 
end view^ resembles the side view of Fig. 44. The upper portion 
(or bearing) is connected with the base by ribs marked Rib A and 
Rib B. On the end view you will again note the same designations 
Rib A and Rib B, which locate the ribs corresponding with those 
in the side view. 

The base is a flat oblong surface, for convenience marked %" 
thick, having four holes — one in each corner. (See top view.) 
The horizontal lines between the side and end views marked 1, 2, 
3, 4, 5, and 6, show the corresponding points of the side and end 
views, as for example : 

Lines 1 and 4 show the height of the bearing, or its vertical 
diameter ; the vertical lines between the side and top views marked 
7 to 16 inclusive show the corresponding points of the side and top 
views. For example : 

Lines 8 and 9 show* the projection of one of the holes in the 
base. 

Lines 10 and 15 show the width or horizontal diameter of the 
bearing. 

Lines 7 and 16 show the horizontal length of the base. 

The end view may be placed as indicated by the dotted outline, 
but it is customary to show it in the relation as here placed. — If it 
were placed in the dotted position, lines 17 and 20, also 18 and 19 
^vould show corresponding points of the two views. 

Lines 1 to 20 do not appear on drawings except perhaps as ex- 
tension lines, but are shown here to assist in a clearer understand- 
ing of projecting one point to another view. 

Important — ^From side view to end view, all corresponding 
points are projected horizontally; from side to top view all points 
are projected vertically. 

89 



SAW HORSE 




Fig. 86 shows a perspective view of a saw horse. No doubt you 
have seen one of these in reality in the shop and will experience 
no difficulty in understanding this figure. 




j'of=> V/^w 




>5fDE Vf^w r/q^sy ^^o V/^y^- 



90 



Fig. 87 shows the arrangement of several views of a working 
drawing of this same horse. Your attention is called to the rela- 
tive position of the top, side and end views as previously explained. 
It is important that you understand the correct projection of each 
line from one view to another and it should be remembered that 
every line on a working drawing has its particular use and shows 
the correct projection of a surface or point from one view to an- 
other, therefore every line should be studied carefully to ascertain 
just what it represents. 

The side braces of this horse are projected to the top view by 
the lines as indicated at A and B. It will be seen by looking at 
the end view that the cross brace is shorter along its upper edge 
than at its lower. This is also indicated on the top view by the 
lines C and D (see also Fig. 86). This is one illustration that each 
and every line on a view represents some particular surface or 
point on one of the other views. 

The end view may have been placed in relation to the top view 
as indicated by the dotted outline in Fig. 85. Views may be rear- 
ranged, but the projecting of one view to another is always the 
same. 



MOLD FOR POURING BASIN. 

Fig. 88 represents a cast iron mold used in making a pouring 
basin. A pouring basin is molded of sand and baked in an oven. 
It is used as a funnel for pouring the liquid metal into a mold. The 
drawing here shown is the cast iron mold for these pouring basins. 

We advise projecting each and every point, etc., from one view 
to another by the use of a rule or straightedge — the projections 
being the same as all examples previously explained. The straight- 
edge should be used horizontally betAveen cross sectional and end 
views, and vertically between the cross sectional and top views. 

Note — In reading this drawing, turn book so that the figure 
number is towards you. The cross sectional view will then be to 
the left of the end view. 

Remember the general outline as well as the complete informa- 
tion can only be obtained by careful study of two or more working 
drawing views of an object. 

91 




The material used is cast iron — the crosshatching as well as 
the notation explain this. 

In this working drawing the end view might have been omitted 
but then all dimensions now shown on it would have been placed 
on the cross sectional view. This may make the cross sectional 
view too congested with dimension lines, and therefore an end view 
is advisable. 

92 



FRICTION DISC. 

Fig. 89. This drawdng represents a friction disc used in the 
transmission of power from one wheel to another. We suggest 
that you make a careful study of this drawing, and try to picture 
or imagine the exact shape and size by comparing the dimensions 
given. Attention is called to the placing of the f mark and of the 
allowable variation dimension of 4.123" zh .005", the meaning of 
which has been previously explained. The use of the degrees is 
also illustrated here. 

After you have carefully investigated this drawing to your 
entire satisfaction and are of the opinion that you thoroly under- 
stand it, we suggest that you make a perspective drawing and then 
turn to page 114 upon which is shown a photograph of this disc. 
By comparison you may readily test the power of your imagination. 




Fig. 89 



This and the following drawings are shown expressly for prac- 
tice in the reading of working draA^dngs, and we earnestly recom- 
mend that you spend sufficient time on each figure to thoroly un- 
derstand it, and if you have mastered the information contained in 
the previous pages, you will experience no difficulty in the reading 
of this drawing. 

'Free hand sketching showing working drawing views of simple 
objects is very good practice and you are earnestly advised to do 
this whenever possible. An ordinary table knife, the exterior views 
of an ink bottle, an empty spool, or house key, are only a few of 
the many simple objects which would afford excellent practice. 




EXAMINATION 
LESSON 10 

1. Fig. 85. (a) How many holes are in the base of object? 

(b) Which single view shows all the holes in base? 

(c) If the top view had been omitted, would the side 
and end views give all the necessary information? 

2. Fig. 89. (a) What is the thickness of the large circular disc? 

(b) What is the outside diameter of this disc in inches? 

(c) What is the total length of the casting? 

3. Fig. 88. (a) What is the diameter of the outer circle shown in 

top view? 
(b) What is the vertical height of casting? 




94 



LESSON ELEVEN 



CLAMP. 




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r 




Ti^'SO. 



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Fig. 90 represents a clamp and is shown to illustrate one method 
of placing a cross sectional view and the importance of a careful 
study of all notations. 

There is no view^ on this drawing which indicates that the head 
(the part thru which the screw passes) is cylindrical, but the nota- 
tion DIA. explains this likcAvise DIA. indicates that the head plate 
is circular, and therefore no other views are necessary. 

The cross section appearing on the \\ang of the thumb screw 
and frame of the clamp indicates the construction of these parts, and 
are practical illustrations of the text on page 62, the crosshatching 
indicating cast iron. 

Two methods of representing threads are also shown — the alter- 
nate heavy and light lines represent threads of external view, and 
the alternate long and short dotted lines of even thickness indicate 
the threads in the head — sho^oi dotted as they exist but are hidden 
from view. 

The partial view at the right is called an auxiliary view as a 
portion only is shown to explain the construction of a certain part 
of the object proper. 



95 



SHAFT COUPLING. 

Figr. 91 represents the working- drawing- of a shaft coupling. 
Two views only are shown as all information necessary to fully 
explain this coupling is covered in these views. We suggest that 
you picture the general shape and outline of this coupling from 
drawing. 




^ /ILL OV£fr. 



Your attention is also called to the construction of the center 
lines, the general outline (thickness of line), the crosshatching 
symbol, the use of the f mark, the section marked AAA indicat- 
ing that the upper right hand portion of the front view is imagin- 
arily removed to produce the upper half section of the side view. 

Referring to page 114 you will see a cut of this coupling and 
will readily be able to check your imaginative ability. Study all 
descriptive matter and notations. The spacing of the bolts is here 
shown as being 60° between each, indicating that the total number 
of bolts is six, as 360° divided by 60 equals 6. 

The diameter of the outer circle is 11%" ; the width of the web 
is 2" ; the hub is tapered toward each end — each end being 51/2^' in 
diameter. 

Review — ^A side view shows only that which can be seen when 
looking directly at the side of the object — the eye being in a direct 
horizontal line with each and every point of its surface and outline, 
with all depressions and extensions brought to the same plane. This 
also applies to an end view. 

A top view is produced in the same manner, except that the eye, 
when looking at the object, is in a direct vertical line with each 
and every point of its surfare and outline. 

96 



FREE HAND SKETCHING. 



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You may be called upon to explain certain operations of manu- 
facture, details of machinery parts, placing of gates and risers, 
construction of cupola with suggestions for its improvement, or 
any other detail pertaining to the mechanical field. By being able 
to explain your point using an intelligently made sketch instead of 
motions with your hand, you will convey a much more convincing 
argument than would be possible otherwise; also it will add to 
your personal knowledge and prestige, therefore we suggest that 
you practice free hand sketching, taking some simple object and 
showing all views necessary to make the reading and understand- 
ing of the object possible. 

A claw or ball hammer, pipe fittings, an ordinary wrench or 
any other object will afford good practice. We have shown a free 
hand sketch of an ordinary bolt, flask pin, handle and hinge. 



97 



DIMENSION LETTERED DRAWINGS. 
ADJUSTABLE FLASKS. 



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98 



Fig. 92 is a working drawing of an adjustable iron flask used 
iti the foundry, the various lines and points being projected from 
one view to another in the same manner as previously explained. 

This dra'v\dng is shown expressly to illustrate the use of dimen- 
sion letters, for example : Take letter A and by referring to the 
table it will be noticed that the dimensions in column A vary from 
48" to 96", indicating that the length of flask may be made to any 
of these dimensions. However, all other corresponding dimensions, 
as B, C, D, etc., must lie in a horizontal line with the desired length 




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(fencer ff£f/foyrso) 



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-Ol. nut. 



TABLE OF DIMENSIONS 

All Dimensions are in Inches 



Size 
No. 


A 


B 


C 


D 


E 


F 


G 


H 


J 


K 


L 


M 


11 


I2OK2 


543^ 


59 


47^ 


703^ 


20 


27 M 


55K 


2434 


48 


12^ 


48 1< 


12 


1365^ 


621^ 


67 1^ 


54i-6 


81^ 


24 


31M 


62A 


2SV2 


60 


14>^ 


553^ 


13 


162^ 


72 


80 


641^ 


953^ 


30 


36 


743^ 


35 


66 


16>^ 


613^ 



N 



27 
31 

37M 



Size 
No. 





P 


Q 


R 


s 


T 


U 


Y 


a 


c 


d 


Shaft 
Dia. 


11 


47^ 


43H 


2^2 


16 


P/8 


5^ 


6 




VA 


16 


H 


5 


12 


53^ 


49^ 


3 


1834 


13^ 


6M 


7 


2^ 


IH 


16 


% 


634 


13 


64 


59^^ 


3 


23 


2 


7^ 


11 


2H 


VA 


20 


1 


7 



99 



in column A. Let us assume -we want to make a flask, the 
dimension A to be 78" — dimension B will then be 10", C 9", D 12", 
E 3", F 6", and G 39". 

Fig. 93 on page 99 is another illustration showing the use of 
a ''dimension lettered drawing," this being a Sturtevant blower 
used for supplying air to a cupola. 

A side, end and auxiliary views are shown. At the right hand 
end of side view you will note a pulley is shown; by referring to 
the end view it will be seen that this pulley has been omitted — 
this is done to explain the construction of some detail back of the 
pulley. 

The auxiliary view at the bottom is not a complete bottom view, 
it shows only the size and number of bolt holes in the feet and 
intake flange. 

The over-all length of blower for a No. 13 size is 162%" and the 
over-all height is 12". 

Note — Refer to the drawing and locate all the letters and their 
dimensions. 

The use of dimension lettered drawings eliminates the necessity 
of making a separate drawing for each size. 

WORKING DRAWING OF BEARING. 

Fig. 94 represents a working drawing of a special bearing. The 
working drawing views of this bearing consist of a side, end and 
bottom view. This is the first illustration in which a bottom view, 
is shown. As explained the bottom view is placed at the bottom 
of either side or end view (in this case at the bottom of the side 
view), and the various points have been projected vertically from 
the bottom to the side view. 

Attention is called to the construction of the center line — it 
being a long dash with one short dash, in all previous drawings 
shown as a long dash with two short dashes. The center line is 
here shown thus to illustrate that a deviation from the regular 
practice may be met with. 

Referring to the bottom and side views one method of indicating 
a tapped hole is here shown (also see page 65, Fig. 62). 

The notations ''1/4" drill for No. 5 taper pin" also '^7/32" drill, 
%"-ll tap," appearing at the right hand of the bottom view, 
explain these two operations. It will be seen that the arrows are 
directed to one of each of these holes, however, there are two of 
each shown in the bottom view. . In the reading of working draw- 
ings it is always understood that any notation explaining a part or 
operation also applies to all similar parts or operations on the 
object, therefore it is not necessary that explanatory notations 
appear at each. 

The distance between the two horizontal dotted lines in the 
side view is 2.00" .-± .001". This represents the bore. 

100 




SPECIFICATIONS 

In some instances one sheet may have the details of several 
pieces shown on it. — This is done to keep the details of correspond- 
ing component parts together and to economize on materials — snch 
as paper and tracing cloth. However, in some shops it is the usual 
practice to show the working drawing views of only one object 
on a sheet, and the drawings showing its component parts are listed 
on a separate sheet called a specification. 

Specifications usually mention all the miscellaneous materials 
which are necessary to complete the machine, giving number re- 
quired, size and material for each item separately — snch as bolts, 
nuts, screws, washers, cotter pins, etc. 

101 




EXAMINATION 
LESSON 11 

1. Fig. 91. (a) What is the length of the coupling? 

(b) What material is coupling to be made of? 

(c) What is the diameter of bolt circle? 

(d) What is the size of hole thru which these bolts 
pass? 

2. If it is desired to make a flask as shown in Fig. 92, 7 feet square 
on the inside, give all the other dimensions which would cor- 
respond with this size. 

3. Fig. 93. (a) What are the over-all length, height and width for 

a No. 11 blower? 

(b) What is the size of holes in the intake flange for a 
No. 13 blower? 

(c) What is the dimension for diameter and face of 
pulley for a No. 11 blower? 

4. Fig. 94. (a) What is the size and kind of hole shown in the 

upper left hand of the bottom view? 

(b) What is the length of the bored hole marked 
2.00" ±: .001" in the end view? 




\ 



102 



LESSON TWELVE 



PRACTICE READING. 

The reading of working drawings is a comparatively easy matter 
if vou will resolve each portion of the object represented into its re- 
spective surfaces and locate the various outlines as they are shown in 
the different projections. If this is found a difficult task, the sur- 
faces may be further resolved into lines and points, whose respective 
positions may then be located in each view shown. 

Practice reading and free hand sketching of simple objects show- 
ing working drawing views will be of great value to you. Working 
drawings of practical objects with an explanation of the important 
points are shoAvn in th^ following lessons. It will be excellent prac- 
tice to make a free hand sketch representing a view not shown on the 
illustration. For example, if a side and end view are shown on the 
illustration, draw a top or cross sectional view. 

It is not to be expected that the position of every surface in a 
complicated drawing will be seen by the beginner at a single glance — 
an expert seldom acquires such proficiency — but as ''practice makes 
perfect," you may, by careful study of the various positions of the 
surfaces composing the solids that are projected in the following 
problems, easily accustom yourself to the more or less complicated 
projections found in the various mechanical and architectural jour- 
nals, in shop drawings, or in such other projection drawings within 
your reach. 

The work covered in these lessons is for practice in reading a 
-working drawing, and it will be to your advantage to understand 
the projection of all parts, points and lines from one view to another. 
Remember all drawings require more or less study to understand 
them and the understanding of an object is possible only by a thoro 
study of all of its views, therefore study these pages very carefully. 

The rules for reading working drawings should be referred to from 
time to time, so that you will become thoroly familiar with them. 

The various examples and illustrations shown are general, and a 
deviation from this practice will be met with. 

In this lesson is shown and explained the reading of practical 
working drawings and again we advise you to use the straightedge 
in the various projections if in doubt or if the eye has not become 
sufficiently trained to substitute the straightedge. 

103 



We suggest that each and every line and point be projected from 
one view to another. This practice is absolutely essential in order 
to acquire accuracy in the reading of working drav/ings. 

Concentrate on what you are reading and do not attempt to study 
unless you can do so undisturbed. 

REVIEW. 

1. The line of vision must be in a direct horizontal line with 
all points along its height, length or width for horizontal 
projections; and in a direct vertical line with all points 
along its length and width for vertical projections. (See 
page 20.) 

2. All depressions and extensions must be brought to the 
same plane. (See page 20; also illustrated in lesson 8.) 

3. Each view represents that which can be seen when look- 
ing directly at the object, Avith a view representing only 
one of its faces — a side, an end, the top or bottom 
visible at a time. 

4. No single view will give all the information necessary to 
explain the object (except very simple objects), there- 
fore two or more views of an object must always be 
studied. 



BEARING CAP. 

Fig. 95 represents a complete Avorking drawing of a bearing cap, 
with all the necessary dimensions for its construction properly placed. 
The three vicAvs shoAvn are side, top and end — the end Adew being 
placed to the right of the top view. 

As explained in Lesson 3 Figs. 21 and 22, all points or sur- 
faces are projected horizontally when views are placed to either 
right or left of a corresponding vieAv, and all points or surfaces are 
projected vertically when a vieAv is placed either above or beloAv a 
corresponding Adew. ■ 

Three center lines are shown betAveen side and top views. The 
center one indicates the center of the cap proper and those on each 
side show the corresponding center of the two end projections. The 
method of analyzing this draAAdng is as follows : 

104 



Looking at the side view, it will be seen that the general outline 
is in the form of a half circle with a projection at each end. The 
top view will show that these projections are round, having a hole 
thru them which corresponds to the dotted lines in the side view. 




jnnT- Ofl^J IRON 



r/a-BB. 



The top view also shows that the half circular portion is 4%" wide 
having an enlarged projection around its outer edge — the radius of 
which is 3%" (see side view). 

The end view shows these enlarged projections as being %" wide. 

The two 1^6 " drill holes are shown dotted in the end and side vi^ws, 
but the holes being in line (see top view) only permit one being 
shown in the side view. The top and end views explain that there 
are two holes, placed 2" apart (see top view). 

305 



IS 

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106 



GEAR WHEEL. 

Fig. 96 is the working drawing for a gear wheel having six oval 
arms. 

. The cross sectional view marked section AA shows the outline 
of the rim, arms and hub. Your attention is again called to the fact 
that the arms are not shown covered with crosshatching. As pre- 
viously explained, it is customary not to Crosshatch arms altho the 
imaginary cut is taken thru them but strictly speaking, they should 
be crosshatched. 

Referring to the front view, note the oval outline which is cross- 
hatched and directly on one of the arms. This indicates the shape of 
the arm. In some instances the arms are made rectangular and in 
that case a rectangle would be shown and crosshatched, instead of 
the oval. 

« 

It is not necessary that the total number of teeth be shown, for 
instance in this case only three are indicated, and sometimes not any 
are shown. The tooth data or table shown at the right gives the in- 
formation necessary for cutting these teeth, namely the total number 
of teeth, the diametrical pitch which gives the number of teeth for 
each inch of pitch diameter. The pitch diameter is the diameter of 
the circle which passes approximately midway between the outside 
diameter and bottom diameter of the tooth. The bottom diameter 
is the diameter at the bottom of two teeth, diametri<3ally opposite. 

When it is desired that the teeth be cast instead of cut, it is cus- 
tomary to show an enlarged view of two or more teeth, giving the 
necessary dimensions so that pattern maker can make the teeth ac- 
cordingly. 

Form a mental picture of the general outline, etc., then refer to 
page 114 upon which is shown a cut of this same gear. 

The bore is given as 6.500" or might have been written 6^2". 



107 







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108 



PUNCHING. 

SINGLE VIEW DRAWINGS. 

Fig. 97 represents a working drawing of a punching, such as is 
used for the magnetic field of small electrical motors. The copper 
winding is woven into the small slots having contracted openings 
at their outside circumference. When a certain detail on drawing 
l)ecomes so small that it is impossible to clearly show the outline 
with its respective dimension, it is customary to show an enlarged 
view of that particular detail — an example of which is given by the 
enlarged view at the right. This view is drawn to a considerably 
larger scale than the punching proper which enables the mechanic 
to more readily see the general outline of the slot and its dimensions. 

ILLUSTRATING THE USE OF LIMIT DIMENSIONS. 

It is only necessary to make one view of this punching as 
the thickness (.014") is mentioned on the drawing. Attention is 
called to the placing of the limit dimensions as this is a good example 
of their use. The dimension 6.004" being the outside diameter, is the 
ideal dimension ; if, however, it were made .006'' larger it would still 
be accepted, but if it were made smaller than 6.004", it would be 
rejected. 



100 



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110 



CENTER REST TOP. 

Fig. 98. This casting illustrates the use of dotted lines, the rep- 
resentation of threads and the use of the f mark. Attention is called 
to the boss shown at B on the side view. It is indicated by a dotted 
circle as it projects beyond the rear surface of object. By referring 
to the end vieiv you will notice that this boss projects %" from the 
center line of the object and is marked 1" dia. The dotted lines thru 
it represent a tapped hole. 

The round boss marked 1" R. and shown at the right hand of the 
side view is not the same thickness as the casting proper and in 
vestigation of the end view will illustrate this and show that this 
thickness is %". 

Attention is called to the proper projection of the surface marked 
A on the side view, to the end view — the letter A representing the 
same surface in both views. By projecting horizontally each point 
or line on the side to the end view, you will readily understand the 
correct projection. 

The notation 1/2" — 13 threads indicates that this hole is to be 
tapped with a %" tap having 13 threads per inch. The 1" diameter 
dimension at the top of the end view indicates that this projection is 
cylindrical. If the notation ''DIA" had been omitted, it would 
have been necessary to show a top view as there is nothing on either 
view indicating the shape of this projection. 

The importance of a careful study of all notations is here illus- 
trated. 



Ill 



SECflON-Rfi 




v. 



S3^|L 



ANGULAR PROJECTIONS. 

In all previous illustrations, the views were placed either horizon- 
tally or vertically in relation to one another. However, in Fig. 99 
the projection of a view is illustrated on an angle with another. 
This is done to show the true projection of the arm 1 — 2. 

The projection of the arm 3 — 4 is shown directly under it. It 
will be noticed that the lines 5, 6 and 7 project the various points 
from the arm 1 — 2, and it will also be seen that a true view is not 
obtained by this projection, therefore the angle projection of arm 
1 — 2 is employed to show its correct construction. 

The cross section marked "Section AA" shows the construction 
of arm proper at the point where line AA passes thru it. However, 
no further cross section or notation appears to indicate the shape of 
the arm at any other point in its length, therefore it is understood 
that the shape is the same thruout its length. To illustrate, the 
shape of arm 3 — 4 is the same as arm 1 — 2. 

The diagonal lines between the angle projected view and top 
view indicate the corresponding points projected. 

112 



EXAMINATION 
LESSON 12 

1. Fig". 95. (a) What is the height of the end projection or lugs, 

which are 2 inches in diameter? (See top view.) 

(b) What is the thickness of metal thru which the two 
5/16-inch drill holes pass? 

2. Fig. 96. (a) What is the length of hub? 

(b) What is the size of bore in hub? 

3. Fig. 98. (a) Hoav many tapped holes are in this casting and 

what size are they? 

(b) How many reamed holes and what size are they? 




113 




The working drawing of this friction disc is shown on page 93. 




The working drawing of this coupling is shown on page 96. 




The working drawing of this gear is shown on page 106. 



114 



LESSON THIRTEEN 



PISTON. 




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Fig. 100 shows the complete information of a piston for an 
automobile engine — top, cross sectional and end views. 

The dotted lines in the top view represent the various points, 
lines or surfaces projected vertically from the cross sectional view. 



115 



The line AA (in top ^aew) passes thru the center of the pis- 
ton, cutting the ribs. Referring to the cross sectional view, you 
Avill note that the ribs are not crosshatched — which is customary, as 
previously explained. The end view shows an exterior view of the 
piston — on which view no dotted lines are shown. To outline the 
interior of the piston with dotted lines on this view is superfluous 
as the interior construction is readily shown on cross sectional and 
top views. 

Referring to the top view, the diameter of outer circle is 
3.625"d=001". Referring to the cross sectional view, the distance 
from the bottom to the center line of the .8125" reamed hole is 1%". 
Thickness of each rib is Vs". 

Vertical height of these ribs is 1-3/16". This dimension is not 
given on the drawing but sufficient information is given so that 
this may be determined as follows: 

Total height of piston is 3%" 

less 1%'' 



1%" = the distance from top of 
piston to center line of the .8125" reamed hole. Now subtract the 
thickness of the top wall, Vs", and one-half of IVg" (the outside dia. 
of the shell around the .8125" reamed hole) or 

1/8 + 9/16 = 11/16 

1- 7/8 
— 11/16 



1-3/16" height of rib. 



SEMI-STEEL PISTONS. 

A very large percentage of pistons is now being made of semi- 
steel. This, is a metal melted in the cupola, containing from 15 to 
50 per cent steel scrap, producing a very close-grained, easily 
machined and stronger metal compared Avith a straight gray iron 
mixture. 

McLain's System of semi-steel mixing has been on the market 
since 1908 and covers the process of making castings of better 
quality at lower cost by the addition of steel scrap to regular cupola 
mixtures. 

All classes of castings made of cupola metal are benefitted by 
the addition of steel scrap — the percentage added depending on the 
section of castings. 

116 



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BASE. 

Fig. 101 represents the working drawing views of a special base 
casting. You will note that on this drawing no dimensions or lines 
are shown projecting from one view to another (except the center 
lines). This drawing will afford an excellent example for practice 
in the correct projection of the various points from one view to 
another. We advise that you locate each individual point, surface 
or line, drawing a pencil line to its corresponding point on each of 
the other views. 

Study Fig. 101 and if you are in doubt, check up by referring to 
Fig. 102. 



117 



For example, you will note the 3^/4'' bore shown at A is also 
shown at A on the side view. This indicates the projection of 
the bore on two of the views ; however, the bore is shown, but not 
indicated on the top view. Dimensions covering all lines or points 
are shown on two views and may be referred to if you do not under- 
stand the projections of the various lines or points shown on Fig. 101. 

You will note that each dimension is shown on two views on 
Fig. 102; however, this was done only to assist you in understand- 
ing Fig. 101, and is not done in actual practice. 




118 




Fig. 103 

Fig. 103 shows a perspective drawing of a cupola A, with a re- 
ceiving ladle B which is supported on two saAV horses C. A simple 
and practical method employed in some shops to tilt this ladle is 
shown. 

The metal flowing from the spout empties into this receiving 
ladle; it is then tilted by the use of the lever handle D and the 
metal allowed to flow from this receiving ladle into hand ladles 
placed under it (hand ladles not shown). 

A cross sectional view showing the interior construction of the 
cupola is shown in Fig. 104. 

The explanation of a shank, similar to the one housing the re- 
ceiving ladle, is given under Fig. 79 and the working drawing views 
of the saw horse are explained under Fig. 87. 



119 




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120 



CUPOLA. 

Fig. 104 illustrates the construction of a cupola. A cupola con- 
sists of a vertical cylindrical steel shell, at the lower end of which 
is an outer casing known as the wind jacket. A charging door thru 
which material is charged into cupola is also shown. Passages con- 
necting the wind jacket to the interior of the cupola are known as 
tuyeres. These permit the air to enter the cupola supplying the 
necessary air for the proper combustion of the fuel. The entire 
cylindrical shell is lined with refractory brick. 

This drawing illustrates the method of showing the construction 
at the various heights, the sections being indicated as AA, BB, 
CC and DD. The arrow at each end indicates the direction the eye 
is supposed to be looking at the section — in this case it is down. 
There are five cross sectional views shown in this drawing — one ver- 
tical half section and four quarter horizontal sections. 

Section AA is taken thru the brick lining above the charging 
door. One quarter section only is shown ; however, it is understood 
that the entire horizontal section at this point is a continuation of 
that shown in the otie-fourth section. 

Section BB is taken thru the lining directly under the charg- 
ing door. 

Section CC is taken thru one of the tuyeres. 

Section DD is taken thru the tap hole. 

Vertically one-half of the cupola is shown in exterior and the 
other half in cross section. 



121 



MOTOR FRAME. 




Fig. 105 



Fig. 105 is the working drawing of a motor frame with all neces- 
sary dimensions. On correctly made working drawings, the dimen- 
sions between certain lines, points, or the size of holes, etc., should 
appear on only one view and not on any other view pertaining to the 
same object. 



122 



The projections are produced the same as previously explained. 
Bear in mind that the section AAA, or the upper left hand corner 
of the side view, is supposed to be removed. The upper half of the 
end view shows the surface imaginarily cut, covered with cross- 
hatching. 

Note: — Study the projection of each line, point or surface from 
one view to another; for example — the counter-bored holes thru 
each of the six pads. Referring to the top view it will be seen that 
these holes are ''off center," the distance being 1" (see end view). 
Also locate these holes in cross sectional view. 

Study the dimensions — form a mental picture of the size and 
thickness of the various parts. 

The oblong with the rounded corners shown in the end view, (4 x 
6"), is an opening in the end of the frame (both ends). 

Project the top and bottom of this oblong. Locate the dotted 
lines indicating the position of the hole. 

Attention is called to the six pads which are shown equally 
spaced around the inside of the frame. You will note the 60° and 
the 30° notations which locate the pads around the circumference. 
Referring to page 66 you Avill readily understand that 60° plus 30° 
is equal to 90° or the i/4 part of a circle. 

A side view shows only the surfaces and outlines visible when 
looking directly at the side view, with the eye in a direct 
horizontal line with each point. An end view shows the surfaces 
and outlines visible when looking directly at the end view, the eye 
being in a direct horizontal line with all points of the surfaces and 
outlines. For top view the eye must be in a direct vertical line with 
all points on the upper surface and with the outline. 

Attention is called to the following notations which appear on 
Fig. 105. The crosshatching indicates that the motor frame is made 
of Past steel. Compare with symbol on page 57. 

The folloAving notations are shown correctly placed, and ex- 
planations will be found on page 54. 

Bore Rad. or R. • Spot Face 

Dia. Drill C. Boi^^ 

^ Center line (note construction) Section AAA 

123 




fJc,- 106 



Vl^ 



BEEHIVE COKE OVEN. 

Fig. 106 is a working drawing of a beehive coke oven and is 
used for the manufacture of foundry and blast furnace coke. It 
is built entirely of refractory brick. The relative position of the 
views of this oven is exactly the same as that of any other object 
previously explained. A doorway is shown at the left and a circular 
tapered opening thru the roof. The general outline of the oven is 
similar to a dome. 

By referring to the top view you will note that one-half of this 
view shows the exterior of the roof when looking directly down oh 
top of it. The lower right hand quarter of the top view indicates a 
cross sectional view taken along the line BB and the lower left hand 
of the top view indicates the cross sectional view taken along the 
line AA, looking down. A longitudinal cross sectional view is shown 
and marked section CC, the section being taken along the line 
CC (see top view). A half view of the doorway looking out from 
the interior is shown at the right. 

Cross sectional views of this oven are obtained in exactly the 
same manner as previously explained. It must be remembered that 
the surfaces which have been cut with the imaginary saw along the 
lines as mentioned are crosshatched. The section lines AA and 
BB indicate the position or location of the horizontal cut and the 
section lines CC on top view indicate the position or location of 
vertical cut thru the oven. 



OPERATION OF BEEHIVE COKE OVEN. 



Beehive coke ovens are used to manufacture foundry and blast 
furnace coke. The dimensions are from 7 to 12 feet in diameter, 
vertical wall 2% feet high and the roof almost hemispherical. These 
ovens are generally arranged in batteries of 20, 30 or more, being 
placed one alongside the other, with the doorways all on the same 
side. 

A retaining wall is built the full length of the battery along the 
door side and up to the top of oven. Earth is then used to cover 
the entire oven, allowing only the top of the upper opening to 
project. A railroad track is placed about 6 or 7 feet to the right of 
this opening, running parallel with the ovens. On this track coal 
is conveyed from the screens or washery to the openings of the 
ovens. The largest size ovens are capable of holding a charge of 
about 5 ton which is introduced thru the opening at the top and is 
leveled off to a height of about 2V2 feet. 

125 



The brickwork of the walls and roof being still red hot from the 
previous charge, ignites the gases. Air is admitted thru openings 
in the upper part of the door. When the gas is burnt off, the upper 
part of the door is opened and the glowing charge cooled by jets of 
water thrown directly upon it from a hose, and it is subsequently 
drawn out thru the open door. The charge breaks up into prisms 
or columns the length of which corresponds to the depth of the 
charge, and as a rule is uniform in character and free from dull 
black patches or "black ends." 

The time for burning is either 48 or 72 hours. The longer the 
heat is continued the denser the product becomes, but the yield also 
diminishes, as a portion of the finished coke necessarily burns to 
waste when the gas is exhausted. For this reason the yield on the coal 
charged is usually less than that obtained in retort ovens, altho the 
quality is better. Coals containing at most about 35 per cent volatile 
matter are best suited for the beehive oven. With less than 2»5 per 
cent the gas is not sufficient to effect the coking completely, and 
when there is a higher percentage the coke is brittle and spongy and 
unsuited for blast furnace or foundry use. The spent flame from the 
ovens passes to a range of steam boilers before escaping by the 
chimney. 



126 



s^ 



EXAMINATION 

LESSON 13 

1. Fig. 100. (a) How many ribs are there in the inside of this 

piston ? 

(b) What is the outside diameter of this piston? 

2. Fig. 102. What are the over-all height, length and width of this 

• casting? 

3. Fig. 105. (a) Which single view shows there are four holes in 

the feet? 

(b) What are the over-all length, width and thickness 
of one of the feet? 

(c) What is the distance from the bottom of feet to 
center line of frame? 




127 



LESSON FOURTEEN 



BOTTOM POUR LADLE. 

Fig. 108 is a general outline and cross sectional view of a bottom 
pour ladle with an adjustable stopper rod and actuating mechanism 
ia position. The cross sectional view shows the stopper rod, sleeves 
and nozzle. 

A bottom pour ladle is used in steel foundry practice. The mol- 
ten metal is poured into this ladle and conveyed to the molds. When 
the nozzle (10) is directly over the gate of a mold, the lever (14) is 
pressed down, which in turn lifts the stopper rod off the nozzle brick 
seat, allowing the metal to flow into the mold. 

Your attention is called to the correct projection of the adjust- 
able slide from the front to the side view. Lever (14) is not shown 
in the side view. 

This being only an outline drawing, it is not necessary to show 
the top view, however the complete detail drawing of the ladle will 
show a top view or the notation dia. 

Fig. 109 shows the complete details of the adjusting device. On 
this figure the details of the several parts are shown and we advise 
studying each detail carefully as to projections — general outline and 
notations. This is a good example of assembly drawings (Fig. 108) 
and detail drawings (Fig. 109). 

The detail drawing for the sleeves, nozzle and stopper is shown 
in Fig. 107. 

Fig. 110 shows one type of bottom pour ladle in use. 




^•pT®*'' otctvc 



Fig. 107 

129 



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130 



BOTTOM POUR LADLE IN USE 




Ficx 110 



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132 



TYPICAL DETAIL DRAWING 

Fig. 109 shows single, two and three view working drawings. 
Items 6, 7 and 9 are single view drawings ; items 2, 3, 4 and 8 are two 
view drawings. Items 1 and 5 are three view drawings. 

Referring to item 1, Fig. 109. The dimension 2%" shown at the 
top of end view indicates that the thickness of casting is 2%". 
Continue down and it will be seen that a 1%'' dimension is given 
from the left hand face to the vertical dotted line — this dotted line 
indicates the depth of slot, which is 2%" wide (see side view). 

The distance from the top to the center of the 1" drilled hole in 
the arm is 25" (20+5) and this hole is 8" to the right of the vertical 
center line of casting proper. The width of the slot in this arm is 
%" and is cored in the casting (see end view). 

A center line is shown 10'' down from the top. There are two 
parallel dotted lines above and below this center line which indicate 
the length of the 1-9/64" drilled hole and the vertical height of the 
projection marked 2%" dia. (end view). The length of this pro- 
jection is 5" (see bottom view). 

Referring to item 2 on Fig. 109. The side view shows an oblong 
1%" wide and 23" long. This view does not explain if the area en- 
closed by these lines is depressed or raised, but by looking at the 
end view it will be seen that it is raised 1". The side view shows a 
1" wide and 7" long cored hole ; the end view explains that this hole 
extends thru the entire thickness. 

Make a study of each item shown on this drawing in a similar 
manner locating the dimensions and lines, points or surfaces they 
refer to. 

Note : — A side view shows only the surfaces and outlines visible 
when looking directly at the side view, with the eye in a direct hori- 
zontal line with each point. An end view shows the surfaces and 
outlines visible when looking directly at the end view, the eye being 
in a direct horizontal line with all points of the surfaces and out- 
lines. For top view the eye must be in. a direct vertical line with 
all points on the upper surface and with the outline. 



133 



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TILTING MECHANISM FOR ELECTRIC FURNACE. 

Fig. 112 is a general outline or assembly drawing of the driving 
mechanism which is used in tilting the hearth of one type of electric 
furnace, thereby alloAving the metal to flow from spout. The two 
channels shown at the top are a part of the framework on the under- 
side of the furnace. 

This drawing is shown for practice in the reading of a drawing 
and affords an especially good example. You are requested to study 
the views carefully, starting with the side view; first follow thru 
the method of driving by starting with the motor and continuing 
until you reach the final joint between the two channels, as shown 
near the top. The general construction consists of a base casting, 
motor, two pedestals, a crank, connecting rod, two pinions, two 
gears, one worm, and one worm wheel. The worm and worm wheel 
are enclosed in a casing, part of which has been broken aw^ay as 
will be noted on the side view. This enables a portion of the worm 
and worm wheel to be shoAvn in full outline. 

By projecting each line or point horizontally from one view to 
another (using a straightedge if necessary) you will readily under- 
stand this drawing. However, if you find it impossible to under- 
stand it, or perhaps are in doubt as to the correctness of your judg- 
ment in the projection, turn to page 136, on which is shown the same 
driving mechanism with each corresponding part indicated with a 
corresponding letter on both views ; some of the construction lines 
also being shown. 

It will benefit you to carefully study Fig. 112 making note of 
each point not clear and after having made these notations refer to 
page 136 to check up. 

Referring to Fig. 112 the lower portion of bearing which carries 
the shaft and pinion G, is not shown on the side view as it would 
become too confusing. The lower half of this bearing is cast in one 
piece with pedestal P. By referring to Fig. 113 the mechanical 
terms for each part are noted. 



135 




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NAME OF PARTS OF TILTING MECHANISM 

A Electric motor 

B Motor pinion 

C Gear 

D Worm 

E Worm Wheel 

F Coupling (shown in one 

view only) 

G Pinion 

H Main gear 

J Crank 

K Connecting rod 

M Gear case 

N Pedestal 

P Pedestal (shown in one 

view only) 

R Base 

Detail of coupling F is shown and explained under Fig. 91. 

Detail of gear C is shown and explained under Fig. 96. 

A general outline drawing does not show the detail construction 
of each component part, hut merely shows the general outline of the 
parts. 



EXAMINATION 
LESSON 14 

1. What reference figures in Fig. 108 indicate the various parts 
shown on Fig. 107? 

2. Fig. 109. (a) How many % inch tapped holes are shown in 

Item 1 ? 

(b) What is the extreme over-all length, width and 
thickness of Item 3? 

(c) What is the over-all length of Item 81 

(d) Why is only one view of Item 7 necessary? 

137 



LESSON FIFTEEN 



GAGGER CASTING MACHINE. 



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Fig. Ill represents a Avater-cooled gagger casting machine or 
permanent mold, consisting of a water-cooled cast iron body having 
gagger molds on both sides, two pedestals, a hand wheel and wheel 
lock, the water being supplied thru pipe B; outlet being C. It is 
used to cast gaggers and is admirably adapted for this purpose. 

In small foundries where every penny counts, the molders are 
instructed to pour gaggers with excess iron instead of scattering it 
thruout the shop, on floors or sand heaps. 

The metal is poured directly into passages forming the gaggers 
— no gates being necessary. The board is then turned over and 
the newly-made gaggers readily drop out. 

As there is another set of gagger molds on the reverse side, it 
is now turned up and permits casting these immediately, providing 
it is the desired size. 

This drawing is what is termed an outline draAving several parts 
being shown but no detail dimensions given. The projection of the 
various points of the hand Avheel are horizontal between the end and 
the side view. 



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140 



Note: — Project the hand wheel to the top view, also bearing cap, 
cap bolts, foot of pedestal, and outline of mold board. 

The mold board is made of cast iron and hollow, so as to allow 
the water to circulate and cool the molds. 

The mold board of some of these machines are made solid, having 
sufficient metal in the mold board to provide the radiation necessary 
for the cooling of the mold. 

PUMP BASE. 

Fig. 114 shows the working drawing views of a special pump 
base, giving side, top, cross sectional and end views. A portion of 
the side view is broken away to explain more clearly the construc- 
tion of the depressed surface at point marked "Section BB" (top 
view). Each point, surface or line should be taken separately and 
its corresponding position located on one or more of the other views. 
For example : the two tapped holes in the top view are also shown 
on the side and cross sectional views — in this manner each and every 
line and point should be taken. 

The line marked AA on the top view indicates the location of an 
imaginary cut. The cross sectional view at left marked "Section 
AA ' ' indicates the surfaces cut. 

If in doubt as to the correct projection of the various lines, etc., 
a rule or straightedge should be used as previously explained. 

Your attention is directed to the two dotted oblongs in the side 
view. It should be understood from the drawing that these oblongs 
indicate holes cut in the side of the base, however, it should also be 
observed that these holes are only in one side. See cross sectional 
view AA and the top view. The short dotted lines in the top view in- 
dicate the location of three oblong holes in the vertical walls of 
base. 

A further investigation will show that one of these holes is 
in one end of this base (see cross sectional view AA). The big sweep 
curve show^s the construction of the rib which is shown on the 
vertical center line in top view. You will notice that the dotted 
oblong shown in this cross sectional view indicates that the cut-out 
portion of base is in the right hand end wall. This is also shown in 
the side view by two short dotted lines and by the outline at the 
right hand showing the end view. 

141 



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342 



ANNEALING BOXES. 

Fig. 115 shows working drawing views of an annealing box — 
side, end and top views, also a cross sectional view at the left of side 
view. The entire box is surrounded by horizontal ribs with vertical 
ribs intersecting. 

Attention is called to the various points projected. Looking at 
the side view you will see two hooks for lifting the entire box. 
These hooks are projected to the top view in the same manner as any 
part of its outline. The cross sectional view shows the shape of this 
hook as the location of the imaginary cut (line AA) will permit a 
full outline of the hook to be shown; however, looking at the end 
view, which is a full outline of the end, you will notice that the 
entire outline of the hook cannot be seen as one of the ribs will pre- 
vent this. Locate this rib in the side view. 

The vertical ribs on each side extend part way up the rounded 
portion of the roof (see dotted lines in cross sectional view). The 
point at which these ribs stop on this curved surface is also indicated 
on the side and top views. Locate these points by projecting the 
top point of the rib in the cross sectional view, horizontally to the 
side view. 

This point or any other may be projected from the cross sectional 
to the top view by measuring a distance as B from the center line 
to the point, and measuring this same distance from the center line 
in the top view to the point ; in this case the point taken was the 
termination of the vertical rib on the roof of box. It will be noticed 
that the point is in vertical line with the rib in the side view. 

This annealing box is used for annealing tin plate. 



143 



MOLDING AND POURING NAILS 





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Fig. 116. Many old-time foundrymen made their own nails by 
taking a board about 12 x 18 x 1" thick and embedding it in the 
top of a sand heap ; it was then removed and numerous holes punched 
vertically into the sand with a ^4" vent wire. Excess iron was 
poured into the pouring basin formed by the 12 x 18'' board. 



In some instances these 12 x 18" boards had holes %" in diameter 
evenly spaced and drilled in them, the vent wire being pushed thru 
these holes and the board acting as a template — later being removed. 

"When sufficiently cool the casting was removed and it looked like 
the perspective drawing in Fig. 117. The long needle-like prongs 
were then broken into desired lengths for nailing the molds. 

Fig. 116 represents working drawing views showing the above 
method of molding these nails, top and side views being shoAvn. The 
irregular outline in the top view sliows the outline of the sand heap 
w^here it meets the floor. Project the extreme width from the top to 
the side view; also project the width of the board and the holes in a 
like manner. 



144 



f3/>0</J- fa/t Sl/^<^. 




SECTIONAL VIEW OF SLAGGING SPOUT. 

A sectional view showing the slagging spout and a portion of 
the interior of a cupola is shown in Fig. 118 B. The fire brick and 
spout for slag are also shown in position. 

The height of crest A is raised to suit ; in some instances it is 
level with the upper edge of tap hole in cupola, but may also be 
carried a trifle higher or lower to suit conditions. This height is 
generally determined by experimenting. 

SLAGGING SPOUT. 

Pig iron and scrap are not always absolutely clean and generally 
have an accumulation of sand and dirt adhering to them. This sand 
and dirt separates from the iron when it is changed to the liquid 
state and forms what is known as slag, Avhich floats on top of the 
mol+en iron. 



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146 



Generally cupolas are provided with an opening in the rear shell, 
so placed that this slag and not the iron will flow from it. However, 
some cupolas allow both the metal and slag to run from the tap hole 
and separate the slag from the iron in the spout. This is accom- 
plished by the use of a slagging spout. When a slagging spout is 
used the rear hole in shell is stopped up. 

This spout is lined with fire brick and a fire clay daubing mix- 
ture. Fig. 118 B. A fire brick is placed crosswise, the lower edge 
of which is about 3" above the 1%" drain hole in the side (see side 
view Fig. 118). As mentioned above, the slag floats on. top of the 
iron and when the metal flows from the cupola, the liquid iron passes 
under this fire brick filling the pocket gradually and rising until 
the lower edge of this fire brick is under the surface of the metal. 
The slag remains on top of the iron and cannot pass under this brick, 
it is therefore trapped by the obstruction caused by the fire brick, 
and will flow off the side thru the opening provided. 

The detail drawing of one of these slagging spouts is shown in 
Fig. 118. 

This drawing shows a zigzag cross sectional view at the right 
and is marked ''Section AAAA. " Referring to the side view, the 
location of this cross section may be found. A top view is placed 
above and shows the tapered end which fits into the recess of the 
cupola ; this taper can only be shown on either a top or bottom view 
and therefore it is necessary that three views be shown of this spout. 

The cross sectional view shows the vertical taper of the spout, 
being 11" across the inside at the top and 9" at the bottom. The 
entire length is 581/2''- This dimension will be found between the 
side and top views. 

Note that the slag hole, which is 5 x 5", the lower corners rounded 
by a V radius, is only shown in one side. This is indicated by the 
cross sectional as well as the top view. 

The auxiliary spout thru which the slag flows is shown in Fig. 
118 A. This spout is provided with two bolt holes for bolting it 
onto the main spout. These bolt holes are Si/^*" apart and the lugs 
foi these are li/4" thick. These holes correspond to those in the 
side of the main spout and are marked ''%"" dia. core." 



147 



B- 


5> 


Ui 


v^ 


^ 






l^ 




l^ji^ -i«vV' 



148 



MALLEABLE IRON FURNACE. 

Working drawing view of a furnace used in the manufacture of 
malleable iron is shown in Fig. 119. The views shown are longitu- 
dinal cross section, horizontal cross section (at top) and two vertical 
transverse half sections thru different locations in the furnace. 

The longitudinal cross section is taken along the line AA 
(see top view) and is an imaginary vertical cut thru the furnace. 

The horizontal zigzag cross section is taken along the line 
CCCC (see longitudinal section) and the surfaces cut by the line 
are shown at the top and marked section CCCC. 

It is supposed that all the portion above the line CCCC is re- 
moved and that the eye is looking down in a vertical line with all 
points, as explained under Fig. 11. 

The location of the cross sectional views at the left are indicated 
by the letters BBBB (see horizontal sectional view at top). 

Details of the construction are as follows : 

The furnace consists of a hearth, fire box and stack. 

The entire furnace is covered with a removable arched roof of 
refractory brick Avhich is held in place by cast iron bungs. Sections 
of roof are removed when charging the material — each ring being 
separate, allows them to be readily removed, and replaced with 
another when it is in need of repairs. 

The heat for melting is obtained from bituminous coal which is 
burnt on the grate, and charged thru the door at side (see top view). 
The air for combustion is vsupplied by force draft thru the blast 
pipe as shown, which enters under the grate. At the upper end of 
this blast pipe a branch pipe runs across the top of furnace with 
numerous smaller pipes entering thru the roof. The additional blast 
at this point further assists in obtaining complete combustion and 
also directs the hot gases onto the charge in the hearth. 

The hot gases from the combustion of the coal are deflected 
downward over the bridge wall by the curved construction of the 
roof. Assisted by the natural draft of the chimney, the gases are 
moved over the hearth and finally go out of the chimney. 

As the scrap and pig melts, it finds its way to the tap hole, the 
sand bottom having been sloped in this direction, and finally the 
liquid meial is tapped and flows from the spout (see horizontal 
section). 

149 



Some malleable furnaces are arranged with a water tube boiler 
placed between the hearth and chimney, and utilize the waste heat 
which would ordinarily travel up the chimney, to generate steam in 
the boiler. 

Three door openings are provided (see horizontal cross section). 

The buck stays and tie rods which bind the entire furnace are 
not shown in this drawing. 




EXAMINATION 
LESSON 15 

1. Fig. 115. How many vertical ribs are there around this anneal- 

ing box? 

2. Fig. 118. (a) What is the thickness of metal in walls of spout? 

(b) What is the distance from bottom of spout to cen- 
ter line of the %-inch diameter bored hole for 
bolting on the auxiliary spout? 

3. Fig. 119. (a) What is the inside width of furnace? 

(b) What is the thickness of side walls? 



150 



LESSON SIXTEEN 



MELTING FURNACES. 

The manufacture of iron and steel begins with the mining of 
the raw material (iron ore) — approximately 85 per cent of which 
is mined in the Lake Superior district, about 8 per cent near 
Birmingham, Alabama, and the balance in New York, Pennsylvania, 
New Jersey, and other States. 

In 1917, 75,288,000 ton of ore Avas mined in America and 
38,621,216 ton of pig iron produced. 

When it is known that approximately 2000 lbs. of coke, 1200 
lbs. of limestone and 4256 lbs. of ore is required to produce one 
net ton of Northern pig, you can appreciate the producers' objec- 
tion to the present high freight rates. 

A cupola (Fig. 104) is a furnace used in the manufacture of 
cast iron. 

A malleable furnace, sometimes called air furnace (Pig. 119) 
is used to manufacture malleable iron. 

A converter (Figs. 121 and 122) is one type of furnace used to 
manufacture steel. 

An open hearth furnace (Figs. 123 and 124) is another type 
used in the manufacture of steel. 

All of these melting units use a percentage of pig iron with 
scrap to produce iron or steel, as the case may be. The pig iron is 
manufactured in a blast furnace (Fig. 120). 

The electric furnace (Fig. 126) is the latest method of producing 
steel. This process requires electric current to generate the neces- 
sary heat. 

The construction of each type of furnace is briefly outlined under 
its respective heading and should prove of interest to the student. 
Complete information on the various methods of producing steel 
is contained in McLain's System of steel foundry practice which is 
the result of a practical investigation of each process. 




Ti^-IEO 



152 



BLAST FURNACE. 

A blast furnace is used to manufacture pig iron from iron ore. 

A cross sectional view of a blast furnace, skip hoist and hopper 
house is shown in Fig. 120. It is to be remembered that this draw- 
ing merely shows one view and is not a complete working drawing. 
However, it is shown to familiarize you with its construction and 
operation. 

The furnace consists of a tall cylindrical shell provided with 
tuyeres at the bottom and a special bell hopper at the top. 

Ore, coke and limestone are the materials necessary to manu- 
facture pig iron. 

Iron ore, the raw material of tlie blast furnaces, is an oxide of 
iron usually more or less contaminated by various impurities, and it 
is the function of the blast furnace to remove the oxygen from the 
iron and to slag off the impurities. Carbon in the form of coke is 
the usual deoxidizing agent and its combustion also furnishes the 
heat necessary to melt the resulting iron and slag. Limestone is 
added as a flux to render the slag more easily fusible. 

The ore, coke and limestone are elevated to the top by cars 
D which are operated by cables. The contents of these cars are 
automatically dumped into the receiving hopper E, . which is 
sealed with a bell valve F and is operated when a charge is to 
enter the furnace chamber. 

The bell valve F also prevents the gases from making their 
escape thru the top, forcing them out of the opening A. 

The blast furnace is provided with a spout and also a slag hole. 
The metal flowing from the spout is run directly into a trough and 
from there into the pig molds. 

Air is introduced into the furnace to assist in the proper uniting 
of the carbon and oxygen. This air is furnished by powerful blow- 
ing engines, which pump it into a large main. From here it is 
piped into hot blast stoves. (Not shown.) 



158 





354 



DESCRIPTION OF HOT BLAST STOVES. 

These stoves are large, vertical cylinders, lined with, refractory 
brick and have numerous chambers and flues — some of which are 
filled with loose bricks set apart and on edge, each layer setting 
crosswise on the other. This brick work is known as checkers. 

The gases exit thru the opening A near the top (see Fig. 120) 
and are piped thru dow^ncomers into the bottom of these stoves from 
where they rise and heat the checker brick and finally pass out of 
the chimney. By regulating a valve system, the gas is then shut off 
and piped into one of the other stoves, three or four stoves being 
used in connection with each blast furnace — the air from the blow- 
ing engines is then pumped into the stove and thru the various pas- 
sages between the checker brick, which have been previously heated. 
The air from the engines absorbs this heat and it is then piped into 
the bustle pipe B which surrounds the blast furnace. From here the 
air is delivered thru numerous smaller pipes into and thru the 
tuyeres C and finally into the furnace. 



SIDE-BLOW CONVERTER. 

Fig. 121 is a general outline — side, end and cross section of a side- 
blow converter. 

A converter consists of a cylindrical steel shell A, lined Avith 
refractory material. This cylinder is suspended between two trun- 
nions which allow the cylinder to revolve. 

The right hand trunnion C is designed to allow the blast pipe 
to extend thru it and make connection with the wind box, which in 
turn connects with the tuyere box (see cross sectional view) and 
finally with the tuyeres. 

Blast is supplied by a positive blower (see Fig. 93). This blast 
is forced thru the tuyeres and over the bath of molten iron oxidizing 
the mixture and thereby eliminating the silicon, manganese and 
carbon of the molten iron which has previously been reduced to the 
molten state in a cupola. 

After the blast is forced over this metal for about 10 to 12 
minutes, it has reduced the above mentioned elements considerably 
and then the desired amount of silicon, manganese and carbon in the 
castings is added in the form of ferro-silicon, ferro-manganese and 
spiegeleisen. 

McLain's System of steel foundry practice gives a complete de- 
tailed description of the manufacture of steel by the converter 
process. 

The cylindrical shell is capable of being tilted back and forth. 
This is done to keep the liquid metal at about the same level with 
the tuyeres during the bloAv. (See cross sectional view.) 

155 




(Q 




Ax 



156 



This tilting is accomplished by the use of an electric motor which 
has a pinion D on the end of its shaft. This pinion engages with 
a spur gear E and this gear is supported by a worm shaft which 
is held in place by two bearings ' F. This worm engages with a 
worm wheel G which is keyed to the main trunnion casting ex- 
tending thru the bearing B. 

The projections of all points between the side and end view are 
horizontal and a careful study should be made of each point, line 
and surface projected. 

Starting with the motor, project all points from the side view to 
the end view, taking note why some lines are dotted and others full ; 
riemember the rules for making projections and refer to these oc- 
casionally. 

The opening at the top is shown as being oval in the side view 
and is a good example of an angular projection. The actual opening 
is round in the end view. 



BESSEMER CONVERTER. 

The Bessemer converter is a furnace used in the manufacture of 
steel. Its construction is similar to the side-blow converter (the ex- 
planation of which is given under Fig. 121), except in the arrange- 
ment of the tuyeres. 

Fig. 122 shows two cross sectional views of a Bessemer converter. 
The one at the left shows it tilted down in position for receiving a 
charge of molten iron which has been previously melted in the 
cupola. It will be noticed that the liquid metal in the converter does 
not interfere with the tuyere openings at the bottom. 

The air which is supplied by blowing engines at 18 to 25 lbs. 
pressure is piped to the trunnion thru it and connects into the wind 
box at the bottom (instead of side as in Fig. 121). 

The converter is then tilted in a vertical position, while at the 
same time the air is being forced thru the tuyeres — an enlarged view 
of a tuyere being shown at C. 

When the vessel is in a vertical position, as at B, the air passing 
thru the liquid metal causes considerable agitation, oxidizes the 
carbon, silicon and manganese (acid process), the chemical reaction 
generating intense heat. When these elements have been re- 
duced to a minimum, the quantity desired in the castings is then 
added in the form of alloys known as spiegeleisen, ferro-manganese 
and ferro-silicon. 

157 



After these additions have been made the vessel is again turned 
down, the liquid steel allowed to drain out into a ladle placed under 
it, and finally conveyed to the mold where it is poured — forming 
castings. 

By comparing Fig. 122 with Fig. 121 you should experience no 
difficulty in forming the mental picture of the exterior views. 



i^<7 M3U:>-3Q 



^^k■;^^■^■^'■'.^■J.C■■^^^^^^^^^v•A^^■C^^^^'^^^^^^^^^^ ^.-vvvyirvyO^ 





OPEN HEARTH FURNACE. 

There are four types of furnaces for making steel — crucible, con- 
verter, electric and open hearth. 

^ The open hearth furnace consists of a hearth, a set of regener- 
ators (sometimes called checker chambers), a reversing valve, a 
stack to furnish draft, and a charging platform. The principle of 
operation is as follows : 

Kefer to Fig. 123. The scrap and pig iron are charged thru the 
doors onto the hearth. When charging is completed the fuel (in 
this case oil) is blown thru the burner A under high pressure, 
50 to 60 lbs., over this scrap and pig iron. In order to increase the 
temperature of this flame sufficiently to melt the scrap and pig iron, 
additional air, which has been preheated, is allowed to mix with the 
flame of the oil, increasing the temperature. 




159 



After pasing over the metal, the gases still contain considerable 
heat, and in order to utilize this, it is passed down thru the uptake 
flue and into one of the regenerator chambers where these gases pass 
thru a series of checker brick work, which are so arranged that the 
gases in passing over them will give up their excess heat to the 
checker brick. The gases, after passing thru this regenerator, pass 
thru the flues, under the reversing valve and finally out of the stack. 

After the gases have passed thru this circuit for about 15 or 20 
minutes, the opposite oil burner B is introduced and burner A 
withdrawn. The reversing valve is then thrown over, allowing the 
air which enters at the top to pass thru the checker brick which has 
just been heated by the Avaste gases as explained. This air, in pass- 
ing thru these bricks, absorbs the heat from them, then passes up 
the uptake flue, mixes with the fuel oil at end of burner, B, passes 
over the metal and down the opposite uptake flue into the opposite 
checker chamber and finally out of the stack. 

Figs. 123 and 124 show the general arrangement and the entire 
construction of the complete open hearth. 

Fig. 123. One-half of the heartli is shoAvn in exterior view and 
the other half in cross section, showing the liquid metal and uptake 
flue, the burner A being in position for melting. The left hand 
checker chamber is shoAvn in exterior vicAV and the right hand in 
cross sectional view. The reversing valve and flue under it are 
sliown in cross section. 




Fig. 125 



im 



Fig. 124 shows a plan view of the uptake flue, a top and horizontal 
cross sectional view of the checker chamber, the flues connecting the 
checker chamber with the flues under reversing valve and the flue 
connection to the stack. 

The longitudinal cross sectional view, section DD shows the 
uptake flue, regenerator chamber, reversing valve and stack in cross 
section. 

The entire checker chamber and hearth are securely held in place 
by structural steel buck stays. 

A photographic cut of the hearth, showing the charging doors, 
and counter balanced sector for raising the center door is shown in 
Fig. 125. The drawing and perspective photo cut shows the original 
2 — 3 ton McLain-Carter furnace. This furnace is capable of melting 
a 3-ton heat, ready to tap out of the spout, in 1 hour 30 minutes — 
truly a wonderful record ! This is possible, due to the shallow bath 
and exceedingly large regenerator which makes it very economical. 

The McLain-Carter furnaces are now built in all sizes up to 30- 
ton capacity. 



ACID AND BASIC MELTING. 

There are two distinct processes in the manufacture of steel in 
the converter as well as in the open hearth and electric furnaces. 
They are the acid and basic. The difference in the melting units is 
in the composition of its lining; the general construction and ar- 
rangement of their mechanical features are the same in both. 

When the furnace is lined with a basic lining, it is capable of 
oxidizing not only the carbon, silicon and manganese but also the 
phosphorus and sulphur, providing, however, the slag is basic. 

In the acid process, the lining is acid, that is a lining rich in 
silicic acid, such as quartz and clay. By the acid process only the 
carbon, silicon and manganese can be oxidized. The sulpliur and 
phosphorus must be controlled by the amount charged. 



161 




EXAMINATION 
LESSON 16 

1, Fig. 121 cross sectional view. Which pedestal is shown in this 
view, B or C ? 

2. Fig. 124. By what section letters is the view marked Avhich 
shows the construction of the flue from the stack to rear wall 
of pit ? 




162 



LESSON SEVENTEEN 



PROCESS OF MAKING A BLUE PRINT. 

It may interest you to know how a blue print is made. A 
draftsman draws his designs or outlines of the various objects on 
Manila paper. A tracing is then made of the outlines by placing 
either a transparent paper or cloth over the outlines on the Manila 
paper and tracing them with a special pen and India ink on this 
transparent paper or cloth. 

When this is completed we have what may be compared with a 
negative in the photographic work — it being the outline of the object 
on the transparent paper or cloth, as the case may be. It is then 
laid face down on a sheet of clear glass, and a sensitized paper 
(known as blue print paper) is laid on the negative with the sensitive 
side against it. It is then clamped in place and exposed to the sun- 
light or some other strong light. In printing the light does not 
penetrate the inked outline of the drawing. After a short exposure 
the clamps are removed and the sensitized paper thoroly washed 
in clear water. The parts upon which the strong light has shone 
turn blue and the parts or lines directly under the inked outlines 
are not affected by the rays of the light, hence show up white. 

There are blue print machines on the market, and instead of ex- 
posing the sensitized paper to the sun light as mentioned above, it 
is exposed to a strong electric light — the sensitized paper is fed 
past these strong electric lights and directly into a tray where it is 
washed. After this it is passed thru a dryer. The complete opera- 
tion is automatic. 

After a tracing has once been made, an unlimited number of blue 
prints can be made from it, involving very little cost. 



103 








V 




•S^\>, vv^' 



I 

I 






I— ( 









164 



ELECTRIC FURNACE. 

There are many types of electric furnaces on the market today — 
the majority of them being used in the manufacture of steel. Ferro- 
alloys are also manufactured in the electric furnace. A more re- 
cent field in which the electric furnace is gaining prominence is 
that of melting brass, gray iron and semi-steel. 

These furnaces are generally operated on three-phase circuits, 
the furnaces being equipped with three electrodes entering thru the 
roof. Heat is generated by the arc which jumps the gap between 
the end of one of the electrodes and into the molten bath, making 
its exit thru the other two electrodes the current reversing at the 
rate of 60 times per second. In other types a bottom connection is 
provided, the current passing down thru the bath and out of the 
lower connection. 

Fig. 126 shows a cross sectional view of a Heroult electric fur- 
nace the construction of which is as follows : 

The furnace shell is of steel plates riveted together, forming in 
plan a circle 13'6" diameter, flattened at the front and back. To 
this shell is fastened a toothed segment A, which gears into a 
stationary rack B, fixed to a concrete bed 5' above the ground 
level. The segment has an arc of 10' radius, and gives a maximum 
tilting angle of 29° to the furnace. To the back of the furnace is 
attached a hydraulic plunger 18" diameter by 4' stroke, which works 
at a pressure of 500 lbs. per square inch. 

The furnace is lined with one 4^/^" course of magnesite brick on 
the bottom with vertical side walls of magnesite, 18'' thick. The bot- 
tom is composed of dead burnt magnesite, 12" deep at the center, 
sloping upward towards the edges to the form of the surface of a 
sphere, 7' 2" radius. The removable roof is composed of silica 
brick, 12" thick. There are 5 doors, 2 on each side and 1 in the 
front over the pouring spout. The side doors are of cast iron lined 
with fire brick, and are operated by steam pressure. 

The furnace works on 3-phase current and the 3 electrodes form 
in plan the apexes of an equilateral triangle of 5' 2" side. The 
electrode holders, which are arranged to carry 24" electrodes (or 
the equivalent in electrodes built up of smaller sections), are con- 
structed of copper castings, bolted to the busbars. They are reg- 
ulated by an automatic device D, by hand, or by controllers, as 
desired. 

For this particular furnace the power is generated at 2200 volts, 
3 phase, 25 cycles, and stepped down at the furnace by means of 
three 750 kilowatt transformers E, which may be adjusted to 
give secondary voltages of 80, 90, 100 or 110 as desired. Ordinarily 
90 volts is used. 

165 



ftfl af*r /'^^ ►■■»»^n 'A^off^ ^^fj '^'**/»'»f^ c««^_p 





u 






166 



PLANT LAYOUT DRAWINGS. 

When contemplating a new plant, an addition or a rearrangement 
of the equipment in an existing plant, it is customary that a con- 
sultation is held and the suggestions of the superintendent, manager 
and foreman are invited. Frequently a layout is prepared by the 
Engineering Department and a consultation is held. 

It is very much desired that all concerned possess a clear under- 
standing of the general arrangement, etc. To enable you to become 
better acquainted with this type of drawing we have shown the 
layout of a foundry. 

Attention is called to the practice employed in indicating the 
location of building columns, door ways, stairs, railroad tracks, etc., 
also various pieces of equipment, namely an outline showing the ap- 
proximate floor space occupied by each piece of individual equip- 
ment. When making this type of drawing it is also customary that 
the north is shown at the top, south at the bottom, east to the right 
hand, and west to the left. Whenever deviating from this practice 
the points of the compass are always indicated. 

Some plant layout drawings also show a cross sectional view of 
the buildings. Fig. 127 shows this type of drawing. The cross 
sectional view at the right shows the relative position of the yard 
crane and other equipment. A little study of this drawing should 
enable you to readily understand it. Each student should not merely 
glance at these drawings but study them and picture the general out- 
line, etc. as they would exist. 

Layouts of machine shops show the location of each machine. As 
it is always desirable to have each operation in the manufacture of 
an article performed with as little manual labor as possible in trans- 
ferring it from one machine to another, it is always desirable to so 
locate them as to make this possible and in some instances mechanical 
means for conveying parts are installed. All this may be shown on 
plant layout draAvings, the detail of the various appliances being 
worked out later and shown on detail drawings. 



167 




1(58 



DIAGRAMMATIC DRAWINGS. 

Diagrammatic drawings show the outline of several pieces of 
equipment, also the various connections between them. However, 
the equipment and the connections are not shown in the relative loca- 
tion as they would actually be placed when installed, but merely 
show the ultimate connections between the several pieces of equip- 
ment. 

Fig. 128 shows a diagrammatic drawing of a complete air-brake 
equipment used on a street car. The various pipe lines diagram- 
matically shown indicate the connection between the several pieces 
of equipment. The electric wire connection from trolley to compressor 
motor is also shown diagrammatically. When actually installed the 
relative positions of the equipment, etc. are entirely changed, but 
the ultimate connections between the several pieces of equipment 
must conform to the diagram. 



^TfIffriN6 RH£0&TnT 




COHNECTIOti DlRGiHm Ton 5HUNT WouND MOTOR. 



169 



DIAGRAMMATIC WIRING DRAWING. 

Fig. 129. This type of drawing is known as a wiring diagram 
and indicates the proper connections of the copper-leads (or wires) 
from the switch and rheostat to the motor. Attention is called to the 
method of indicating that one lead crosses another as shown at A. 

In making the actual connections however, the leads are not 
placed in the relative position to one another as shown on this draw- 
ing, but are run in a manner best suited to the local conditions. 
Ultimately each lead must make its proper corresponding connection, 
with switch, rheostat or motor, as the case may be, regardless of the 
direction of the leads. 



REPAIR PART DRAWINGS. 

Manufacturers of articles which are more or less complicated 
furnish the purchasers with a Repair Part List, which generally has 
a cut showing all the working parts. Fig. 130 is a repair part list 
and drawing of a special valve. 

From the cross sectional view here shown it is not possible to 
form a picture of its general outline, etc. As has been previously 
mentioned, it is always necessary to refer to more than one view to 
clearly understand a drawing. However, this drawing was not made 
for the purpose of showing the detail of each component part but 
that each and every part of valve proper could be recognized when 
compared with the drawing and by referring to the reference figure 
and descriptive matter at the bottom, the name and its piece num- 
ber are given. Both should always be used when it is found neces- 
sary to order a duplicate part. 

Attention is called to the crosshatching (refer to page 57). 
Parts 1 and 17 are crosshatched to represent cast iron and parts 2 
thru 8 represent cast brass. 

Attention is also directed to the method of showing screw threads 
(14). Note the head of screw is not shown with crosshatching. 
Note method of showing a cross sectional view of spring (9 and 10). 

The tapered thread at each end indicates a pipe tap. 

When purchasing equipment which is more or less complicated it 
is advisable to insist on getting a repair part list and sketch show- 
ing the several parts. 

170 




Fi<^'/30 



National Release Valve 



Code Word 



Bazzicargo 

Bazzicater 

Bazzicaul 

Bazzicavil 

Bazzichoir 

Beach tarn 

Beackoran 

Beacon less 

Beacon rise 

Beadlebeak 

Beadleglim 

Beambox 

Beamcable 

Beamcase 

Beamtread 

Beancrop 

Beardless 

Bearskin 



Ref. 


Piece 


No. 


No. 




8300 


1 


8301 


2 


8302 


3 


8116 


4 


8117 


5 


8118 


6 


8119 


7 


8120 


8 


8121 


9 


8122 


10 


8123 


11 


8124 


12 


8125 


13 


8303 


14 


8126 


15 


6149 


16 


8304 


17 


8305 



Name of Part 



Valve body with bushing, including 8301-8302. 

Valve body 

Bushing . . .• 

Piston 

Valve stem ." 

Piston 

Exhaust valve bushing 

Strainer frame and screen 

Packing ring 

Spring 

Spring 

Gasket 

Gasket 

Gasket 

R. H. M. screw, per 100 

R. H. M. screw, per 100 

Hex. hd. cap screw, per dozen 

Cover 



171 




172 



VALVE BODY 

Ammonia valve castings are made to mthstand a working pres- 
sure of 3000 lbs. per square inch. It had been found impossible to 
make these with an ordinary gray iron mixture — however, by the 
addition of 30 to 50 per cent steel scrap the grain was closed, sec- 
tions reduced and a more easily machined casting produced. 
McLain's System of mixing by analysis and cupola practice made 
this possible. 

Fig. 132 represents a working drawing of an ammonia valve 
seat. The views shown are side (half external and half section), 
top, right hand (half external and half section), and left hand (half 
external and zigzag cross section). 

At first glance this dra^dng may appear to be a trifle complicated 
but by taking each line, surface or point separately — one at a time — 
and projecting it to the other views in the same manner as on all 
previous drawings, it will soon resolve itself into a comparatively 
easily understood working drawing. 

It is advisable to project the lines and surfaces of the general 
outline first — projecting all points between side and top views ver- 
tically and between view to either right or left of side view hori- 
zontally. 

The half sectional view of the side view shows the construction 
of the interior in full lines — the imaginary cut being taken along 
line AA (top view) will disclose these. The surfaces cut are covered 
with erosshatching. The left half of side view shows exterior 
view — the construction of the interior being shown by the use of 
dotted lines. 

The right hand end view also shows a half cross sectional and 
half exterior view. By referring to the top view it is supposed that 
the lower right hand quarter is imaginarily removed to produce the 
cross sections shown in the side and right hand end views. 

The left hand end view shows two one-quarter sectional views 
at different locations in the valve proper. See lines C, D, E and F 
in side view. The upper right hand quarter section is produced by 
the imaginary cut being taken on line CD. 

The lower right hand quarter section is produced by the 
imaginary cut being taken on line EF. 

173 



The top flange is 4%" square and the corners are rounded with 
a y<2,' radius. Thickness of flange is V^' . The right and left hand 
(langes are 4I/2" square, have a i/o" radius in each corner and are 
%" thick. The extreme height of the valve is 5-13/16" ; the extreme 
length is 8". 

There are twelve %" tapped holes in the three flanges. The 
depth of the counter bored holes, which are marked 2" dia. in the 
end flanges and 2%" dia. in the top flange, are y^' . 

The diameter of the neck of the valve where it meets the end 
flanges is 214" diameter. 

. Note: — Locate the above mentioned details and dimensions. 



PATENT OFFICE DRAWINGS. 

Patent office drawings are made on special paper, known as 
Bristol board. The outside dimensions of sheets are 10 x 15", and 
the border line 8 x 13" — no part of drawing to be closer than 1^/4" 
from the upper border line. The title of drawing must be written 
on the back sheet with pencil. 



In the lower left hand corner space is reserved for the witnesses ' 
signatures and in the lower right hand corner, space is reserved for 
the inventor's and his attorney's signatures. All signatures must 
be written with black ink. 

These drawings are made using shaded lines and line shading. 
Accompanying these drawings is a descriptive text of the apparatus 
in detail, explaining the operation of the mechanism by the use of 
reference letters which appear on the drawing. 

Fig. 131 is an illustration of a patent drawing. 



174 



No^ 820,591 



M 



PATENTED MAY 15, 1906. 
D. MoLAIN. 
MOLDING FLASK OR BOX. 

APPLICATION FILED AUG. 17. 1900. 








j^^-^ 




& iO // 



J^J 




f/yyi/ SZZj>t^M^ /J- ^y 



/^ Jit 



^ ^?? z^e'// ^o?^ 



Fig. 131 



175 



UNITED STATES PATENT OFFICE. 

David McLain, of Milwaukee, Wisconsin, Assignor of One-Half to 
Niels Anton lOhristensen, of Milwaukee, Wisconsin. 



MOLDING FLASK OR BOX. 

No. 820,591. Specification of Letters Patent. Patented May 15, 1906, 
Application filed August 17, 1900. Serial No. 27,117. 

To all whom it may concern: 

Be it known that I, David McLain, a resident of Milwaukee, 
5 in the county of Milwaukee and state of Wisconsin, have in- 
vented certain new and useful improvements in molding flasks 
or boxes, of which the following is a specification. 

My invention pertains to molding flasks or boxes; and the 
object thereof is to improve the construction of such flasks, 
making them, preferably, of structural iron- work, such as 
I-beams or channel-bars, and also provide for interchange- 
ability of the boxes. 

My invention also contemplates a novel and advantageous 
15 clamp for the flasks. 

In the drawings. Figure 1 is a plan vicAV of one of my 
boxes or flasks; Figures 2 and 3, sections on lines 2 2 and 3 3, 
20 respectively, of Figure 1 ; Figure 4, a section on line 4 4 of 
Figure 2 ; Figure 5, an elevation of the clamp ; Figure 6, a 
section on line 6 6 of Figure 5, and Figure 7, a fragmentary 
view of a modified form. 



176 




EXAMINATION 
LESSON 17 

1. Fig. 132. (a) Are all flanges the same thickness? 

(b) On how many views is it indicated that the top 
flange is to be finished? 

(c) Is the distance between centers of tapped holes in 
all flanges the same? 

(d) What is the distance from center line to the top 
face of upper flange? 

(e) Are all flanges the same size? 



177 



LESSON EIGHTEEN 



The following lessons contain tables and useful information which 
have been selected with care as we believe they will meet the 
requirements and prove useful to those tradesmen who follow this 
course of instruction. 

The information contained in these tables has been selected from 
various handbooks, trade papers and publications. 

The formulas on pages 201 to 205 inclusive, covering the areas 
and volumes of the various shaped surfaces and objects, have been 
condensed to their simplest form and the explanation given on page 
197 gives a thoro understanding of the formulas. 

The explanation and example on page 211, showing how to esti- 
mate the weight of a casting, illustrates the method which must be 
followed when estimating the weight of any casting; namely, that 
each and every part of the object must be taken separately, resolved 
into some familiar geometrically-shaped object, and the cubic inches 
(volume) calculated, using the formulas on pages 203 to 205. The 
total number of cubic inches in each component part is added and 
the sum multiplied by the weight of 1 cubic inch of the material 
from which it is made. 

The weights per cubic inch of various materials are listed on 
pages 219 to 221. 



179 



WEIGHTS AND MEASURES 

Measures of Length 

1 mile = 1760 yards = 5280 feet. 
I yard = 3 feet = 36 inches. 
I foot =12 inches. 
The following measures of length are also used occasionally: 
I mil = o.ooi inch, i fathom = 2 yards = 6 feet. 
I rod = 5.5 yards = 16.5 feet, i hand = 4 inches, i span = 9 inches. 

Surveyor's Measure 

I mile = 8 furlongs = 80 chains. 

I furlong = 10 chains =220 yards. 

I chain = 4 rods =22 yards = 66 feet = 100 links. 

I link = 7.92 inches. 

Nautical Measure 

I league = 3 nautical miles. 

I nautical mile (knot) = 6080.26 feet = 1.1516 statute mile. 
One degree at the equator = 60 nautical miles = 69.168 statute miles. 360 de- 
grees-- 21,600 nautical miles = 24,874.5 statute miles = circumference of earth at 
the equator. 

Square Measure 

I square mile = 640 acres = 6400 square chains. 
I acre = 10 square chains = 4840 square yards = 43,560 square feet. 
I square chain =16 square rods = 484 square yards =4356 square feet. 
I square rod = 30.25 square yards = 272.25 square feet = 625 square links. 
I square yard = 9 square feet. 
I square foot =144 square inches. 
An acre is equal to a square, the side of which is 208.7 feet. 

Measure used for Diameters and Areas of Electric Wires 

I circular inch = area of circle i inch in diameter = 0.7854 square inch. 
I circular inch = 1,000,000 circular mils. 
I square inch = 1.2732 circular inch= 1,273,239 circular mils. 
A circular mil is the area of a circle o.ooi inch in diameter. 

Cubic Measure 

I cubic yard =27 cubic feet. 
I cubic foot= 1728 cubic inches. 
The following measures are also used for wood and masonry: 
I cord of wood = 4X4X8 feet =128 cubic feet. 
I perch of masonry = i6| X 12 X i foot = 243 cubic feet. 

Shipping Measure 

For measuring entire internal capacity of a vessel: 

I register ton = 100 cubic feet. 
For measurement of cargo: 

I U. S. shipping ton = 40 cubic feet = 32.143 U. S. bushels = 31.16 Imperial 

bushels. 
I British shipping ton= 42 cubic feet= 33.75 U. S. bushels = 32.72 Imperial 
bushels. 



180 



WEIGHTS AND MEASURES 

Dry Measure 

I bushel (U. S. or Winchester struck bushel) = 1.2445 cubic foot= 2150.42 

cubic inches. 
I bushel = 4 pecks = 32 quarts = 64 pints. 
I peck = 8 quarts = 16 pints. 
I quart - 2 pints. 

I heaped bushel = i\ struck bushel. 
I cubic foot = o.8o,s6 struck bushel. 
I British Imperial bushel = 8 Imperial gallons = 1.2837 cubic foot = 2218.10 

cubic inches. 

Liquid Measure 

I U. S. gallon = 0.1337 cubic foot = 2u cubic inches = 4 quarts = 8 pints. 

I quart = 2 pints = 8 gills. 

I pint = 4 gills. 

I British Imperial gallon = 1.2003 U S. gallon =277.27 cubic inches. 

I cubic foot = 7.48 U. S. gallons. 

Old Liquid Measure 

I tun = 2 pipes = 3 puncheons. 

I pipe or butt = 2 hogsheads = 4 barrels =126 gallons. 

I puncheon = 2 tierces = 84 gallons. 

I hogshead = 2 barrels = 63 gallons, 

I tierce =42 gallons. 

I barrel =312 gallons. 

Apothecaries' Fluid Measure 

I U. S. fluid ounce = 8 drachms = 1.805 cubic inch = ^l28 U. S. gallon. 

I fluid drachm = 60 minims. 

1 British fluid ounce = 1.732 cubic inch. 

Measures of Weight 
Avoirdupois or Commercial Weight 

I gross or long ton = 2240 pounds. 

I ntt or short ton = 2000 pounds. 

I poimd =16 ounces = 7000 grains. 

I oimce =16 drachms = 437.5 grains. 
The following measures for weight are now seldom used in the United States: 

I hundred-weight = 4 quarters =112 pounds (i gross or long ton = 20 hundred- 
weights); I quarter = 28 pounds; i stone = 14 pounds; i quintal = 100 
pounds. 

Troy Weight, used for Weighing Gold and Silver 

I poimd =12 ounces = 5760 grains. 

I ounce = 20 pennyweights = 480 grains. 

I pennyweight = 24 grains. 

I carat (used in weighing diamonds) = 3.168 grains. 

I grain Troy = i grain avoirdupois = i grain apothecaries* weight. 



181 



FRACTIONS OF AN INCH AND EQUIVALENT DECIMALS 



Fractions 




Decimals 


Fractions 




Decimals 


of an 




of an 


of an 




of an 


Inch 




Inch 

1 


Inch 




Inch 


1 

64 


,, 


.015625 


33 
64 


^_ 


. .515625 


1 
3 2 


= 


.03125 


17 
32 


= 


.53125 


3 
64 


= 


.046875 


M 


= 


.546875 


1 
16 


= 


0625 


1^ 


= 


.5625 


5 
64 


= 


078125 


H 


= 


.578125 


3 
32 


= 


.09375 


19 
32 


= 


.59375 


7 
64 


s= 


109375 


39 
64 


= 


.609375 


Vs 


= 


.125 


Vs 


= 


.625 


9 
64 


= 


. 140625 


li 


^ 


.640625 


5 
32 


^ 


15625 


1^ 


= 


.65625 


11 
6 4 


^ 


.171875 


43 
64 


^■ 


.671875 


^ 


= 


.1875 


n 

16 


= 


.6875 


H 


= 


.203125 


45 
6 4 


= 


.703125 


7 
32 


= 


.21875 


23 
32 


= 


.71875 


H 


= 


.234375 


47 
64 


= 


.734375 


H 


= 


.25 


H 


= 


.75 


17 

64 


= 


.265625 


M 


= 


.765625 


9 
32 


= 


.28125 


25 
32 


= 


.78125 


H 


= 


.296875 


5JL 
64 


= 


.796875 


A 


= 


.3125 


13. 
i6 


= 


.8125 


H 


= 


.328125 


S3 
64 


=: 


.828125 


H 


= 


.34375 


27 
3 2 


= 


.84375 


M 


s= ' 


.359375 


55 
6 4 


= 


.859375 


^8 


= 


.375 


Vs 


= 


.875 


25 
64 


= 


.390625 


57 
64 


:= 


.890625 


H 


= 


.40625 


29 
32 


= 


.90625 


27 
64 


= 


.421875 


59 
64 


= 


.921875 


7 
1 f. 


= 


.4375 


15 
16 


= 


.9375 


H 


= 


.453125 


61 
64 


= 


.953125 • 


M 


^ 


.46875 


31 
32 


= 


.96875 


li 


=: 


.484375 


63 
64 


= 


.984375 


H 


= 


.5 


1 in. 


^^ 


1.000000 



HOW TO USE DECIMALS. 

Let us assume that an inch in length represents one dollar in 
monev. Then : 

% dollar equals 50 cents or $.50 

% inch equals .50 inches in a decimal 

1/4 dollar equals 25 cents or $.25 

% inch equals .25 inches in a decimal 

% dollar equals 75 cents or $.75 

% inch equals .75 inches in a decimal. 



182 



As mentioned, i/^ equals .50 — the small dot before the 5 is called 
a "decimal point." Each figure to the right of this point is called a 
decimal place; example, in .509 there are three decimal places (the 
also counts as a place). In 20.96207 there are two places to the 
left of the decimal point ; however these are not decimal places but 
whole numbers. The five places to the right of the decimal point are 
decimal places. 



1/10 


(One tenth) 


is written 


.1 


5/10 


(Five tenths) 


is written 


.5 


5/100 


(Five hundredths) 


is written 


.05 


55/100 


(Fift:y five hundredths) 


is written 


.55 


5/1000 


(Five thousandths) 


is written 


.005 


55/1000 


(Fifty-five thousandths) 


is written 


.055 


555/1000 


(Five hundred fifty-five thousandths) 


is written 


.555 


5/10000 


(Five ten-thousandths) 


is written 


.0005 



Eeferring to the decimal, you will note that the value becomes 
less the farther it is moved to the right of the decimal point. 



ADDITION OF DECIMALS. 

If you know how to add different sums of money, you will readily 
understand how to handle decimals. For instance : 

You know that 50 cents is half a dollar, therefore it is 50 parts 
of the hundred cents or fifty one-hundredths, and is written .50. One 
dollar and seventy-five cents is one and three-quarters dollars, and 
is written $1.75, or one and seventy-five hundredths. $2.25 is read 
two dollars and a quarter, or two and twenty-five hundredths. In 
adding decimals, you do the same as in adding money. 

It is important to keep the decimal points directly under one 
another and add as in the ordinary way. 

.50 
1.75 
2.25 



4.50 



SUBTRACTION OF DECIMALS. 



It is again important that the decimal points be placed directly 
under one another and subtracted in the same manner as whole 
numbers. Examples : 



3.25 
-1.75 



.5625 
—.4375 



1.50 



.1250 



183 



MULTIPLICATION OF DECIMALS. 

The decimal equivalent table will be found very convenient in 
multiplying fractions. For example : Let us suppose we wish to 
multiply % X %' 



// 



s/s" = .375 (Multiplicand) 
%"-=.625 (Multiplier) 



1875 
750 
2250 

.234375 Answer (Product) 

The decimal point before the 2 in the answer must be used with 
care. In order to know w^here to place the decimal point in the 
answer, add the number of decimal places to the right of the dot 
in the .375, and those to the right of the dot in the .625, which equals 
six. Start at the right hand figure in the answer and count six 
figures to the left, and set this dot before the sixth figure. In this 
case it is the 2. 

Important. Remember, you only count the number of decimal 
places to the right of the dot in the multiplicand and multiplier and 
do not pay any attention to those to the left, if there are any, as 
tliese are whole numbers. For example: 

Multiply 278 X 301/8 2.875 (%==.875, see decimal equiva- 

X30.125 (1/8--=. 125, lent table. 



14375 
5750 

2875 
86250 

86.609375 

Note : — Be sure to count the total number of decimal places to the 
right of the dot, regardless of how many there may be. 

The decimal equivalent table will also be found useful in multi- 
plying the thickness of a casting by its length and width ; especially 
when the thickness is less than 1 inch, or a fraction over 1 inch. For 
example : 

T%" thick = .5625 

1^%'' thick = 1.5625 
5i%" thick = 5.5625 



9_ 

"6 



(If the casting is 10" x 15" x 1^- 
10 X 15 X 1.5625 = 234.3750 cubic inches) 

184 



DIVISION OF DECIMALS. 

You will note there are three terms used in division; namely, 
divisor — dividend — quotient, or answer. 

Example : 

Quotient 



Divisor J Dividend 

This form should be used when dividing. 

The placing of the decimal point in the quotient is one of the 
important things to watch in the division of decimals. 

Rule: — If the number of decimal places in the dividend is less 
than the number in the divisor, annex ciphers to the dividend until 
there are as many or more decimal places as in the divisor. Divide 
as in whole numbers, and point off as many decimal places in the 
quotient as there are more decimal places in the dividend than in 
the divisor. 

It is a simple operation to divide a large number by a smaller 

one, thus : 

_5 

2J 10 

But when dividing a small number by a larger one, it is more 
confusing. Let us assume we wish to divide 2 by 10. 



10 J 2 

We know that 10 is not contained in 2, so we place a decimal 
point after the 2 and add 0, thus : 

-10 fTo" 

Now divide as in whole numbers and point off one place in the 

quotient. 

.2 

10 J 2.0 

20 

Accorr'ing to the rule there is one more decimal place in the div- 
idend than in the divisor, therefore one place is pointed off in the 
quotient. 

In pointing off decimal places in the quotient, start counting from 
the right to the left. 

185 



If it is desired to divide .2 by 10, the operation is done in 

exactly the same way : 

.02 

10 J .20 

20 



One has been added after the 2 in the dividend and the 10- is 
now contained in 20. Divide as in whole numbers and point off two 
places in the quotient as there are two decimal places more in the 
dividend than in the divisor. 

Now let us divide .02 by 10. 

.002 



10 J .020 
20 



Again a has been added after the 2 in the dividend and the 
division made as tho they were whole numbers, pointing off three 
places in the quotient. 

A more complicated problem, presents itself when we wish to 
divide 2 by .10 



.10 J 2 The first thing to do is to place a decimal point after 
the 2 and add as many O's as there are places to the right of the 
decimal point in the divisor, thus, 



.10 J 2.00 Then divide as tho you were dividing whole numbers, 
paying no attention to the decimal, thus: 

20 
.10 J 2.00 The answer will be 20. 

There being as many decimal places in the dividend as in the 
divisor, will make the answer a whole number. 

Let us divide .005 by .0006. 



.0006 J .005 Here we have 4 decimal places in the divisor and 
only 3 in the dividend (O's count as places) therefore we add one 
after the 5 thus : .0006 J .0050, making the number of decimal 
places the same in both dividend and divisor, and then divide as in 
whole numbers. 



186 



8.33 
.0006 J .005000 
48 

20 

18 

20 
18 

Point off two places in the quotient as there are four in the 
divisor, which subtracted from the six in the dividend leaves two. 

PROOF OF DIVISION. 

Division may be proved by multiplying the quotient by the divisor 
which should equal the dividend. 




EXAMINATION 
LESSON 18 

1. What is the decimal equivalent of 49/64, 7/32, 27/32? See table 
of decimal equivalents. 

2. How many yards in a mile ? 

3. How many cubic feet in a cubic yard? 

4. How many pounds in a long ton? 

5. Write 27-23/32 inches in a decimal. 



1ST 



LESSON NINETEEN 



AREAS OF SQUARES AND CIRCLES. 

In Fig. 139 we have shown a square surface 2 x 2" — the area of 
this square will be 4 sq. in. Now let us make each side of this square 
twice as large, or 4 x 4" (Fig. 140) — the area will then be 16 sq. in. 
As you will see, we have made the side of the original square twice 
as large, but the area has been increased four times (16 is 4 times as 
much as 4) . This also applies to circles. 

Referring to Fig. 141 we will try to explain that a 1" diameter 
circle has only about % the area of a 1'' square. By referring to 
the figure you will readily see that by cutting away the corners of the 
square, we will have an outline of a circle — the area of which will be 
approximately % of that of the original square, or to be exact, .7854 

We found the area of the square by multiplying the length of one 
side by the length of the other. If we substitute the letter d for 
the length of one side, the area of the square may be written d x d ; 
and the area of the circle being approximately % of that of the 
square its area is then written d x d x .7854. 

Fig. 142 is a circle 2" in diameter. Let us double this diameter 
to 4" (Fig. 143) and the area of the 4" circle will be four times as 
much as the 2'' circle, altho the larger circle is only twice the diameter 
of the smaller one. 

Let us write this out in figures : The area of the 2" circle equals 
2 X 2 X .7854 = 3.1416 sq. in. ; the area of the 4'' circle is 4 x 4 x .7854 
= 12.5664 sq. in. It will be seen that the area of this 4" circle is 
four times that of the 2" circle. 

Examples covered in Fig. 139 to 143 inclusive cover surface 
area only, and we will now show a few examples covering volume. 



VOLUME OF CUBES. 

Fig. 144 is a cube 2x2x2'' and Avill contain 8 cu. in. In Fig. 
145 we have made the side of the cube 4", or doubled the length, 
width and depth of the cube in Fig. 144. The cubic inches in Fig. 
145 will be 4 X 4 X 4'' = 64 cu. in. ; or the 4" cube has eight times 
as much volume as the 2'' cube and for this reason will also Aveigh 
eight times as much, if made of the same material. 

189 



flfS^^^ 



H 






M 






/G 3^ M 



r 



i 



/v^- /^o 




*y 



kV^ 




/7^- /-<i/ 



/-/<5- /^f 




7x<Sr- /^3. 



^OUU M£^^. 




p^- /44 



<c>4- CU. Itsl. 




p<Si- /4(^ 



pG,- /^J 




p(^- /4a 




T/^-/4f. 



190 



VOLUME OF SPHERES. 

We have explained that the volume of a cube is equal to the 
length multiplied by the width, multiplied by the depth. In Fig. 146 
we have shown a sphere placed inside of a cube and have assumed 
that the length of a side of this cube is 1" and that the diameter of 
the sphere is also 1". If this block were made of wood and we were 
to cut away the 8 corners making a 1" diameter sphere, we would 
only have about V2 o^ the original volume of the cube left in the 
sphere, the exact figure being .5236. 

As we explain that .7854 is the area of a 1" circle and is used as a 
base on which to figure the area of circles of any diameter — and 
.5236, being the volume in cubic inches of a 1" ball or sphere, it is 
used as a base on which to figure the volume of balls or spheres of 
any diameter. In other words, to find the volume of a sphere or ball 
is the same as figuring the volume of a cube (length of side equal 
to diameter of sphere) less the 8 corners, the figure .5236 making 
the allowance for the volume in cubic inches of the 1" sphere or ball. 

If we insert the letter d in place of the 1" dimension for the 
side of the cube, the volume of the cube will be written d x d x d and 
the volume of the sphere will be written d x d x d x .5236. 

Fig. 147 is a ball 6" in diameter and the volume is equal to 6 x 6 
X 6 X .5236, which equals 113.10 cu. in. Fig. 148 is a 12" ball— the 
volume is equal to 12 x 12 x 12 x .5236 = 904.78 cu. in. 

A 12" ball (Fig. 148) weighs 8 times as much as a 6" ball (Fig. 
147) (not twice as much), altho the 12" ball is twice the diameter of 
the 6" ball; and an 8" ball (Fig. 149) weighs about 2.4 times as 
much as a 6" ball — or almost 21/2 times. 

WEIGHT OF BALLS. 

The weights of the 6, 8, and 12-inch balls will be in the same 
ratio as the volumes if made of the same material. 



191 



CIRCUMFERENCES AND AREAS OF CIRCLES FOR 
DIFFERENT DIAMETERS. 

On pages 192 to 196 you will find tables giving the areas and 
circumferences of circles for various diameters. This table may be 
used to advantage in finding the areas of pipes, surfaces, flues, etc. 
Attention is called to the column headed ''Circumferences." The 
circumference of a circle is the distance around its outer edge and is 
equal to the diameter multiplied by 3.1416. 

The area of a circle is found by multiplying the diameter by the 
diameter by .7854, or may be written d^ x .7854 — (d^ indicating that 
the diameter is multiplied by itself). It should be remembered that 
area represents only flat surface with no thickness. 



Diam. 


Circum-. 


Area 


Diam. 


Circum. 


Area 


^ 


.04909 


.000192 


4 


12.5664 


12.5664 


A 


.09818 


.000767 


4M 


12.9591 


13.3641 


A 


. 19635 


.003068 


4M 


13.3518 


14.1863 


H 


.3927 


.012272 


4H 


13.7445 


15.033 


A 


.589 


.027612 


^H 


14.1372 


15.9043 


H 


.7854 


.049087 


Ws 


14.5299 


16.8002 


A 


.98175 


.076699 


^H 


14.9226 


17 7206 


Vs 


1 . 1781 


.110447 


4K 


15.3153 


18 6555 


A 


1.37445 


. 15033 








H 


1.5708 


. 19635 


5 


15.708 


19.635 


A 


1.76715 


.248505 


^Va 


16.1007 


20.629 


Vs 


1.9635 


.306796 


5H 


16.4934 


21.6476 


H 


2, 15985 


.371224 


5^ 


16.8861 


22.6907 


H 


2.3562 


.441787 


5H 


17.2788 


23.7583 


H 


2.55255 


.518487 


5^ 


17.6715 


24.8505 


Vs 


2.7489 


.601322 


5H 


18.0642 


25.9673 


H 


2.94525 


.690292 


5K 


18.4569 


27.1086 


1 


3.1416 


.7854 


6 


18.8496 


28.2744 


IH 


3.5343 


.99402 


6H 


19.2423 


29.4648 


IH 


3.927 


1.2272 


6M 


19.635 


30.6797 


IH 


4.3197 


1.4849 


6H 


20.0277 


31.9191 


IH 


4.7124 


1.7671 


6H 


20.4204 


33.1831 


IH 


5.1051 


2.0739 


evs 


20.8131 


34.4717 


\H 


5.4978 


2:4053 


6H 


21.2058 


35.7848 


iH 


5.8905 


2.7612 


&H 


21.5985 


37 1224 


2 


6.2832 


3.1416 


7 


21.9912 


38.4846 


2H 


6.6759 


3.5466 


7H 


22.3839 


39.8713 


2K 
2H 


7.0686 


3.9761 


7M 


22.7766 


41.2826 


7.4613 


4.4301 


7H 


23.1693 


42.7184 


2M 


7.854 


4.9087 


7H 


23.562 


44.1787 


2^ 


8.2467 


5.4119 


7H 


23.9547 


45.6636 


2H 


8.6394 


5.9396 


7H 


24.3474 


47.1731 


2H 


9.0321 


6.4918 


7H 


24.7401 


48.7071 


3 


9.4248 


7.0686 


8 


25.1328 


50.2656 


3H 


9.8175 


7.6699 


SVh 


25.5255 


51.8487 


3K 


10.2102 


8.2958 


8H 


25.9182 


53.4563 


3H 


10.6029 


8.9462 


8H 


26.3109 


55.0884 


3H 


10.9956 


9.6211 


8H 


26.7036 


56.7451 


SH 


11.3883 


10.3206 


SH 


27.0963 


58.4264 


SH 


11.781 


11.0447 


8H 


27.489 


60.1322 


3V$ 


12.1737 


11.7933 


SVs 


27.8817 


61 . 8625 



192 



Circumferences and Areas of Circles 

continued 



Diam. 


Circum. 


Area 


Diam. 


Circum. 


Area 


9 


28.2744 


63.6174 


15 


47.124 


176.715 


9H 


28.6671 


65.3968 


153^ 


47.5167 


179.673 


9M 


29.0598 


67.2008 


15M 


47.9094 


182.655 


9H 


29.4525 


69.0293 


15^ 


48.3021 


185.661 


93^ 


29.8452 


70.8823 


153^ 


48.6948 


188.692 


9^ 


30.2379 


72.7599 


15^ 


49.0875 


191.748 


QH 


30.6306 


74.6621 


15M 


49.4802 


194.828 


m 


31.0233 


76.5888 


15K 


49.8729 


197.933 


10 


31.416 


78.54 


16 


50.2656 


201.062 


lOH 


31.8087 


80.5158 


163^ 


50.6583 


204.216 


lOM 


32.2014 


82.5161 


16>i 


51.051 


207.395 


10^ 


32.5941 


84.5409 


16^ 


51.4437 


210.598 


103^ 


32.9868 


86.5903 


163^ 


51.8364 


213.825 


105^ 


33.3795 


88.6643 


165^ 


52.2291 


217.077 


lOH 


33.7722 


90.7628 


16M 


52.6218 


220.354 


10^ 


34.1649 


92.8858 


16K 


53.0145 


223.655 


11 


34.5576 


95.0334 


17 


53.4072 


226.981 


113^ 


34.9503 


97.2055 


nVi 


53.7999 


230.331 


lUA 


35.343 


99.4022 


17H 


54.1926 


233.906 


ilH 


35.7357 


101.6234 


nH 


54.5853 


237.105 


11 H 


36.1284 


103.8691 


173^ 


54.978 


240.529 


im 


36.5211 


106.1394 


17H 


55.3707 


243.977 


llH 


36.9138 


108.4343 


17^ 


55.7634 


247.45 


nvs 


37.3065 


110.7537 


n% 


56.1561 


250.948 


12 


37.6992 


113.098 


18 


56.5488 


254.47 


123^ 


38.0919 


115.466 


i^H 


56.9415 


258.016 


1234 


38.4846 


117.859 


18M 


57.3342 


261.587 


■ 12^ 


38.8773 


120.277 


18H 


57.7269 


265.183 


123^ 


39.27 


122.719 


183^ 


58.1196 


268.803 


12^ 


39.6627 


125.185 


185^ 


58.5123 


272.448 


12M- 


40.0554 


127.677 


185^ 


58.905 


276.117 


12>g 


40.4481 


130.192 


18^ 


59.2977 


279.811 


13 


40.8408 


132.733 


19 


59.6904 


283.529 


133^ 


41.2335 


135.297 


193^ 


60.0831 


287.272 


131^ 


41.6262 


137.887 


19>i 


60.4758 


291.04 


13^g 


42.0189 


140.501 


19^ 


60.8685 


294.832 


133-^ 


42.4116 


143.139 


19H 


61.2612 


298.648 


13^ 


42.8043 


145.802 


195^ 


61.6539 


302.489 


l^H 


43.197 


148.49 


19M 


62.0466 


306.355 


ISVs 


43.5897 


151.202 


19Ji 


62.4393 


310.245 


14 


43.9824 


153.938 


20 


62.832 


314.16 


143^ 


44.3751 


156.7 


203^ 


63.2247 


318.099 


1434 


44.7678 


159.485 


2034 


63.6174 


322.063 


im 


45.1605 


162.296 


20^g 


64.0101 


326.051 


i-^y? 


45 . 5532 


165.13 


203^ 


64.4028 


330.064 


i^% 


45.9459 


167.99 


20^8 


64.7955 


334.102 


14M 


48.3386 


170.874 


203^ 


65.1882 


338.164 


im 


46.7313 


173.782 


20K 


65.5809 


342.25 



193 



Circumferences and Areas of Circles 

continued 



Diam. 


Circum. 


Area 


Diam. 


Circum. 


Area 


21 


65.9736 


346.361 


27 


84.8232 


572.557 


21^ 


66.3663 


350.497 


27% 


85.2159 


577.87 


21M 


66.759 


354.657 


27% 


85.6086 


583.209 


21H 


67.1517 


358.842 


27% 


86.0013 


588.571 


21i4 


67.5444 


363.051 


27% 


86.394 


593.959 


21H 


67.9379 


367.285 


27% 


86.7867 


599.371 


21H 


68.3298 


371.543 


27% 


87.1794 


604.807 


21H 


68.7225 


375.826 


27% 


87.5729 


610.268 


22 


69.1152 


380.134 


28 


87.9648 


615.754 


22H 


69.5079 


384.466 


28% 


88.3575 


621.264 


22>i 


69.9006 


388.822 


28% 


88.7502 


626.798 


22^ 


70.2933 


393.203 


28% 


89.1429 


632.357 


22H 


70.686 


397.609 


28% 


89.5356 


637.941 


22% 


71.0787 


402.038 


28% 


89.9283 


643.549 


22% 


71.4714 


406.494 


28% 


90.321 


649.182 


22 Ji 


71.8641 


410.973 


28% 


90.7137 


654.84 


23 


72.2568 


415.477 


29 


91 . 1064 


660.521 


23H 


72.6495 


420.004 


29% 


91.4991 


666.228 


23>i 


73.0422 


424.558 


29% 


91.8918 


671.959 


2ZH 


73.4349 


429.135 


29% 


92.2845 


677.714 


23 J^ 


73.8276 


433.737 


29% 


92.6772 


683.494 


23H 


74.2203 


438.364 


29% 


93.0699 


689.299 


2ZH 


74.613 


443 015 


29% 


93.4626 


695.128 


2ZH 


75.0057 


447.69 


29% 


93.8553 


700.982 


24 


75.3984 


452.39 


30 


94.248 


706.86 


243^ 


75.7911 


457.115 


30% 


94.6407 


712.763 


24>i 


76.1838 


461.864 


30% 


95.0334 


718.69 


24% 


76.5765 


466.638 


30% 


95.4261 


724.642 


24% 


76.9692 


471.436 


30% 


95.8188 


730.618 


24% 


77.3619 


476.259 


30% 


96.2115 


736.619 


24% 


77.7546 


481.107 


30% 


96.6042 


742.645 


24% 


78.1473 


485.979 


30% 


96.9969 


748.695 


25 


78.54 


490.875 


31 


97.3896 


754.769 


25% 


78.9327 


495.796 


31% 


97.7823 


760.869 


25% 


79.9254 


500.742 


31% 


98.175 


766.992 


25f^ 


79.7181 


505.712 


31% 


98.5677 


773.14 


25^ 


80.1108 


510.706 


31% 


98.9604 


779.313 


25% 


80.5035 


515.726 


31% 


99.3531 


785.51 


25% 


80.8962 


520.769 


31% 


99.7458 


791.732 


25% 


81.4889 


525.838 


31% 


100.1385 


797.979 


26 


81.6816 


530.93 


32 


100.5312 


804.25 


26% 


82.0743 


536.048 


32% 


100.9239 


810.545 


26% 


82.476 


541.19 


32% 


101.3166 


816.865 


26% 


82.8597 


546.356 


32% 


101.7093 


823.21 


26% 


83.2524 


551.547 


32% 


102.102 


829.579 


26% 


83.6451 


556.763 


32% 


102.4947 


835.972 


26% 


84.0378 


562.003 


32% 


102.8874 


842.391 


26% 


84.4305 


567.267 


32% 


103.2801 


848.833 



194 



Circumferences and Areas of Circles 

continued 



Diam. 


Circum. 


Area 


Diam. 


Circum. 


Area 


33 


103.673 


855.301 


39 


122.522 


1194.593 


331^ 


104.065 


861.792 


393^ 


122.915 


1202.263 


33M 


104.458 


868.309 


39% 


123.308 


1209.958 


33^ 


104.851 


874.85 


39H 


123.7 


1217.677 


333^ 


105.344 


881.415 


393^ 


124.093 


1225.42 


33^ 


105.636 


888.005 


39^ 


124.486 


1233.188 


33^ 


106.029 


894.62 


39% 


124.879 


1240.981 


33^ 


106.422 


901.259 


39K 


125.271 


1248.798 


34 


106.814 


907.922 


40 


125.664 


1256.64 


343^ 


107.207 


914.611 


40H 


126.057 


1264.51 


3414 


107.6 


921.323 


40% 


126.449 


1272.4 


34^ 


107.992 


928.061 


40^ 


126.842 


1280.31 


343^ 


108.385 


934.822 


403^ 


127.235 


1288.25 


34^ 


108.778 


941.609 


40^ 


127.627 


1296.22 


34M 


109.171 


948.42 


40% 


128.02 


1304.21 


347^ 


109.563 


955.255 


iOH 


128.413 


1312.22 


35 


109.956 


962.115 


41 


128.806 


1320.26 


351^ 


110.349 


969. 


413^ 


129.198 


1328.32 


35M 


110.741 


975.909 


41% 


129.591 


1336.41 


35V8 


111.134 


982.842 


41M 


129.984 


1344.52 


351^ 


111.527 


989.8 


413^ 


130.376 


1352.66 


SoVs 


111.919 


996.783 


41^ 


130.769 


1360.82 


35% 


112.312 


1003.79 


41% 


131.162 


1369. 


35M 


112.705 


1010.822 


41Ji 


131.554 


1377.21 


36 


113.098 


1017.878 


42 


131.947 


1385.45 


363^ 


113.49 


1024.96 


423^ 


132.34 


1393.7 


36 >i 


113.883 


1032.065 


42% 


132.733 


1401.99 


36^ 


114.276 


1039.195 


42^ 


133.125 


1410.3 


3634 


114.668 


1046.349 


423^ 


133.518 


1418.63 


36^ 


115.061 


1053.528 


425^ 


133.911 


1426.99 


sm 


115.454 


1060.732 


42% 


134 . 303 


1435.37 


36K 


115.846 


1067.96 


42^ 


134.696 


1443.77 


37 


116.239 


1075.213 


43 


135.089 


1452.2 


373^ 


1L6.632 


1082.49 


433^ 


135.481 


1460.66 


37K 


117.025 


1089.792 


43% 


135.874 


1469.14 


37^ 


117.417 


1097.118 


43^ 


136.267 


1477.64 


373/2 


117.81 


1104.469 


43J^ 


136.66 


1486.17 


37^ 


118.203 


1111.844 


43^ 


137.052 


1494.73 


37M 


118.595 


1119.244 


43% 


137.445 


1503.3 


37K 


118.988 


1126.669 


43J^ 


137.838 


1511.91 


38 


119.381 


1134.118 


44 


138.23 


1520.53 


383^ 


119.773 


1141.591 


443^ 


138.623 


1529.19 


38M 


120.166 


1149.089 


44% 


139.016 


1537.86 


38^ 


120.559 


1156.612 


44^ 


139.408 


1546.56 


383^ 


120.952 


1164.159 


443^ 


139.801 


1555.29 


385^ 


121 .344 


1171.731 


44^ 


140.194 


1564.04 


38% 


121.737 


1179.327 


44% 


140.587 


1572.81 


38^ 


122.13 


1186.948 


44^ 


140.979 


1581.61 



195 



Circumferences and Areas of Circles 

continued 



Diam. 


Circum. 


Area 


...... 

Diam. 


Circum. 


Area 


45 


141.372 


1590.43 


51 


160.22 


2042.82 


45H 


141.765 


1599.28 


52 


163.36 


2123.71 


45>i 


142.157 


1608.16 


53 


166.50 


2206.18 


45H 


142.55 


1617.05 


■54 


169.65 


2290.21 


451^ 


142.943 


1625.97 


55 


172.79 


2375.82 


455i 


143.335 


1634.92 


56 • 


175.93 


2463.01 


45M 


143.728 


1643.89 


57 


179.07 


2551.75 


45J^ 


144.121 


1652.89 


58 


182.21 


2642 . 08 








59 


185.35 


2733.97 








60 


188.50 


2827.43 


46 


144.514 


1661.91 


61 


191.64 


2922.46 


46H 


144.906 


1070.95 


62 


194.78 


3019.07 


46J4 


145.299 


1680.02 


63 


197.92 


3117.24 


46^ 


145.692 


1689.11 


64 


201.06 


3216.99 


461^ 


146.084 


1698.23 


65 


204 . 20 


3318.30 


465^ 


146.477 


1707.37 


66 


207.35 


3421.18 


465^ 


146.87 


1716.54 


67 


210.49 


3525.65 


467^ 


147.262 


1725.73 


68 


213.63 


3631.68 








69 


216.77 


3739.28 








70 


219.91 


3848.45 


47 


147.655 


1734.95 








47H 


148.048 


1744.19 


71 


223 . 05 


3959.19 




148.441 


1753.45 


72 


226.19 


4071.50 


473^ 
473^ 
47^ 
4754 


148.833 
149.226 
149.619 
150.011 


1762.74 
1772.06 
1781.4 
1790.76 


73 
74 
75 
76 


229.34 
232.48 
235.62 
238.76 


4185.38 
4300 . 84 
4417.86 
4536.45 


47J^ 


150.404 


1800.15 


77 
78 


241.90 
245.04 


4656.62 
4778.36 








79 


248.19 


4901.66 








80 


251.33 


5026.54 


48 


150.797 


1809.56 








48>^ 


151.189 


1819. 


81 


254 . 47 


5153.00 


48M 


151.582 


1828.46 


82 


257.61 


5281.01 


4&^ 


151.975 


1837.95 


83 


260.75 


5410.59 


481^ 


152.368 


1847.46 


84 


263.89 


5541.77 


48^ 


152.76 


1856.99 


85 


207.04 


5674 . 50 


48^ 


153.153 


1866.55 


86 


270.18 


5808.80 


48K 


153.546 


1876.14 


87 


273 . 32 


5944 . 67 








88 


276.46 


6082'. 11 








89 


279.60 


6221.13 








90 


282.74 


6361.72 


49 


153.938 


1885.75 








49H 


154.331 


1895.38 


91 


285.88 


6503 . 87 


4914 


154.724 


1905.04 


92 


289.03 


6647.61 


49^ 


155.116 


1914.72 


93 


292.17 


6792.90 


• 491^ 


155.509 


1924.43 


94 


295.31 


6939.78 


49^ 


155.902 


1934.16 


95 


298.45 


7088.21 


49^ 


156.295 


1943.91 


96 


301.59 


7238.23 


49J^ 


156.687 


1953.69 


97 


304 . 73 


7389.81 








98 


307 . 88 


7542.96 








99 


311.02 


7697.68 


50 


157.08 


1963.5 


100 


314.16 


7853.97 



196 



FORMULAS. 

In mathematics formulas are used to define rules by the use of 
symbols instead of words. 

When this symbol + is placed between two figures, 9 + 2, it in- 
dicates that 2 is to be added to 9. 

"When this symbol — is placed between two figures, 9 — 2, it in- 
dicates that 2 is to be subtracted from 9. 

When this symbol x is placed between two figures, 9 x 2, it in- 
dicates that 9 is to be multiplied by 2. 

When this symbol -f- is placed between two figures, 9 -f- 2, it in- 
dicates that 9 is to be divided by 2. If written with a figure above 
and. below, 9 it also indicates that 9 is to be divided by 2. 
2~ 

We advise you to work out several of the above formulas, substi- 
tuting any figures you may decide upon. 

Let us assume we write the rule for finding the volume of a cube : 

Length multiplied by width multiplied by height. 

The above expressed by the use of a formula in which symbols 
and letters are used may be expressed as V =^ b x c x h (see page 203 
Fig. 165) , in which V == volume, b ^= length, c = width, h = height. 

It is not always the practice to use x when it is desired to mul- 
tiply two dimensions, and the above formula maj^ be A"\Titten — V = 
b c h — it being understood that b is multiplied by c and this product 
by h, when the letters are grouped without a symbol between them. 

Example illustrating the use of a formula : 

Take the formula for finding the volume of a cone (see page 204 
Fig. 169). 

Y =.: d2 X .7854 X -^ 

o 

Let us assume the diameter (d) of the cone at its base is 9" and 
that the height (h) is 12" ; using these figures in place of the letters 
in the formula, it is written 

V = 92x.7854x-^ 

197 



The small letter placed above and to the right of the 9 indicates 
that 9 is to be multiplied by itself (9 x 9 ^ 81). The formula may 
again be written as follows : 

V = 81 X .7854 X 4 

which, when multiplied out, is 

81 

X.7854 



324 
405 
648 
567 

63.6174 
x4 



254.4696 cubic inches. 

V = 254.4696 cubic inches. 

b 
Assume we have a formula which reads ' ' a = — . " This is known 
as an equation. c 

Rule. It should be remembered that the factor below the line, 
multiplied by the one on the other side of the equation sign (=) 
must equal the factor above the line. Regardless of how you re- 
arrange this formula, this must hold true. 

Example: 

Values : a = 10 b = axcor substituting the values 20 = 10 x 2 

b 20 

b = 20 c = — or substituting the values 2 = — 

a 10 

b 20 

c = 2 a = — or substituting the values 10 = — 

c 2 

Let us work out a practical problem to illustrate the above : As- 
sume we have a fan which is belt driven to a motor and we want to 
determine the size pulley on fan shaft to give a certain fan speed ; 
the rule is 

Speed of fan x dia. pulley = speed of motor x dia. pulley. 

This is an equation similar to the above and we will substitute 
the following values in the equation : 

198 



a ^= speed of fan, 900 R. P. M. (revolution per minute) 
c -= diameter of fan pulley, 8" 
b = speed of motor, 1200 R. P. M. 
d := dra. of motor pulley, 6" 

(a) (c) (b) (d) 

900 X dia. of fan pulley = 1200 x 6 

(c) (b) (d) 

dia. of fan pulley = 1200 x 6 

■ = 8'' 

900 
(a) 

c X a 8 X 900 

b — or b = = 1200 

d 6 

b X d 1200 X 6 

a = or a = = 900 

c 8 

axe 900 X 8 

d = or d = = 6" 

. b 1200 




EXAMINATION 
LESSON 19 

1. What are the area and circumference of a IS-Ys ii^ch diameter 
circle? See table. 

2. What are the area and curcumferenee of a 49-% inch diameter 
circle? 

3. What is the volume of a cone if the diameter of its base is 15 
inches and its height 24 inches. 

4. When no symbol is placed between two letters in a formula, 
Avhat operation is understood to be performed? 

199 



LESSON TWENTY 



AREAS AND VOLUMES OF VARIOUS SHAPED FIGURES. 

A = Area 

d or D := Diameter 

V = Volume, cubical contents. 



SQUARE 

a is 10", find the area. 
A = 10 X 10" = 100 sq. in. 



PARALLELOGRAM 

a is 10" and b 15", find the area. 
A = 10 X 15" = 150 sq. in. 



TRAPEZOID 

a is 10", b 15" and h 8", find the area. 

(10 + 15) X 8 25x8 
A = = = 100 sq. in. 



TRIANGLE 

b is 10" and h 8", find the area. 

10 X 8 
A = = 40 sq. in. 



RECTANGLE 

a is 10" and b 15", find the area. 
A = 10 X 15" = 150 sq. in. 




Assaz 8 



or 



As=a*. 



t— ^ 



^'«75/ 



T 
I 



A SB a X b. 



£C7 



A e= a z b. 



r/«%- ise 






A = 



(• -t- b) h 
2 



//<|- /^ 




b h 
2 



//<?-/^ 



201 




b h 



A = 




A = 3.464 X r X r 



or 3.464 x t^. 



f'G,-)56 




A = 3.314 X r X r 



or 3.314 X r2. 



Fig, - /sy 




A = .215 X r X r 
or .215 X r2. 



A'<f- /Ss 




A = .7854 X D X d. 



nc-is<i 




A = d2 X .7854 



F'q-/eo 




A = .7854 (D + d)(D — d). 



Ffc,-/ci 



RIGHT ANGLE TRIANGLE 

b is 10" and h 8", find the area. 
10x8 



A 



— 40 sq. in. 



HEXAGON 

r is 10", find the area. 

A = 3.464 X 10 X 10" = 346.4 sq. in. 



OCTAGON 

r is 10", find the area. 

A = 3.314 X 10 X 10" = 331.4 sq. in. 



FILLET 

r is 10", find the area. 

A = .215 X 10 X 10" = 21.5 sq. in. 



ELLIPSE 

D is 15" and d 10". find the area. 
A = .7854 X 15 X 10" = 117.81 sq. in. 



CIRCLE 

d is 10", find the area. 

A = 10 X 10 X .7854 = 78.54 sq. in. 



CIRCULAR RING 

D is 20" and d 10", find the area. 
A = .7854 (20 + 10) (20 — 10) = 

.7854 (30) (10) = .7854 x 300 = 

235.62 sq. in. 



202 



SEGMENT 

r is 20". 1 31.4", h 5.8" and c 28", find 

the area. 
A = ^ [20x 31.4 — 28 (20 — 5.8) ] = 
^ [628 — 28 (14.2)] = 

230.4 

% [628 — 398.6] = --= 

2 116.2 Bq. in. 



CIRCULAR SECTOR 

r is 10" and 1 20", find the area. 
10x20 



= 100 6q. in. 




A = »/2 [r I - c (r - h)). 



A>«;-/6? 



/ \/-rA A = J/i X r X L 



/>«- /C3 



Diride the area into equal spaces and find the n« of the partial 
areas. If the figure is very irregular, the approximate area may be 
found as follows: 

Divide the figure by parallel lines, b, c, d, etc. The lengths of 
these lines being measured, then, calling a the first and i the last 
length, and y the width of strips, 
a 4- i 

A = y I ^.b-fc + d+e-ff+g + h 




(a -H 
— 



) 



F'^'/€4 



IRREGULAR AREA 

a ia 3", b 7". c 9". d 10", e 10", f 9". g 9", h 5", i 5", y 3", find the area. 
3 + 5 



A = 3 



/3 + 5 \ 

I 1-7 + 8 + 10 + 10-1-9 + 9 I - 3 X 57 = 171 sq. in. 



CUBE 

b is 8", c 8" and h 8", find the volume. 
V = 8 X 8 X 8 = 512 cu. in. 



PRISM 

b is 8". c 8" and h 20", find the volume. 
V = 8x 8 X 20 = 1280 cu. in. 



PYRAMID 



b is 12", c 12" and h 20", find the volume. 

12 X 1^ X ;:o 

V = == 960 cu. in. 

3 




V == b X e X b. 



r/<i- /63 



T 
i 



ZZ^ 



3=^ 



V = b X c X h. 



ri<i' /6* 




b X e X h 



V = 



203 




V = area of base x — 
3 



/><»• /6S 




^ V = d^ X .7854 X — 



Fig,- J<><f 



t— J //<5-/ 




Fi<i- no 



V = .2618 h X (D' + D d + d^). 



/v^- Hi 




V = — w h (a + b + c). 
6 




V = .5236 X d X d X d 



or .5236 x d^ 



Fig,- 172 




V = 2.4674 D X d*. 




V = d» X .7854 X h 



REGULAR PYRAMID 

Area of base 150 sq. in., height 20", find 
the volume. 

150x20 
V = = 1000 cu. in. 



CONE 

d is 10" and h 24", find the volume. 

24 
V = 10 X 10 X .7854 X — = 628.32 cu. in. 

3 



FRUSTUM OF CONE 

D is 12", d 10" and h 8", find the volume. 
V = .2618 X 8 X (144 + 12 x 10 + 100) = 
2.0944 X 364 = 762.3616 cu- in . 



WEDGE 

w is 10", h 24", a 12", b 28" and c 30". 
find the volume. 



V = — X 10 X 24 (12 + 28 4- 30) = 

6 2800 cu. in. 



SPHERE OR BALL 

d is 9", find the volume. 

V = .5236 X 9 X 9 X 9 = 381.7044 cu. in. 



RING 

D is 10" and d 2", find the volume. 
V = 2.4674 X 10 X 2 X 2 = 98.6960 cu. in. 



PORTION OF CYLINDER 

d is 4" and h 8", find the volimie. 
V = 4 X 4 X .7854 x 8 = 100.5312 cu. in. 



204 



CYLINDER 

d is 4" and h 10", find the volume. 
V = .7854 X 16 X 10 = 125.664 cu. in. 



HOLLOW CYLINDER 

D is 20", d 8" and h 30", find the volume. 
V = (400 — 64) X .7854 x 30 =7916.83 cu. in. 



A 




V = .7854 X d2 h. 





nci- fjG 



V = (D2 — d2) X .7854 X h 



Area of one end x h. 



The area A of the end surface is found by the 
formulas for areas of plane figures on the preceding pages. 
Distance h must be measured perpendicular to end surface. 



r/<5 '/77 



HOW TO ESTIMATE THE WEIGHTS OF VARIOUS SHAPED 
OBJECTS WHEN MADE OF DIFFERENT MATERIALS. 

It willbe of value to you to know how to estimate the weight 
of any object and following is the simple rule which must be fol- 
lowed when estimating weights : 

Find the cubical contents of the object and multiply this by the 
w^eight of 1 cubic inch of the material from which it is made. (Cu- 
bical contents means the number of cubic inches contained in an ob- 
ject.) 

When multiplying a length by a width, or a length by a height, 
square inches or square feet are obtained as the case may be ; but 
when multiplying either of the above by a third dimension (depth), 
the result is cubic inches or cubic feet, indicating the cubical con- 
tents of the object. Let us explain this by an example: 



1 


■" 




■ 


*— 


ft 

— Co — 


— » 






O ^ 


" «o 










■ 


k 













A 



Fig. 178 

205 



SQUARE INCH AREA. 

Fig. 178 represents a block which has been marked 6" long, 5" 
wide and 3'' high. The area of one side will be 6 x 3 = 18 sq. in. — 
or the length multiplied by the height, gives square inches. 

CUBIC INCH. 



By multiplying this square inch area by the depth, 5", we obtain 
cubic inches, and the total operation may be written 6x3x5" = 
90 cu. in. 

We will now proceed to explain how the weight of this block is 
obtained. Referring to page 219 you will note the column headed 
''Weight per Cubic Inch." In this column the weights for one 
cubic inch of the various materials mentioned in the left hand 
column are given. 

We will assume the block. Fig. 178, is to be made of cast iron 
and by referring to the column headed ''Weight per Cubic, Inch," 
we see that .26, or approximately i/4 lb., is the Aveight given for each 
cubic^inch of iron. We previously found that this block contained 
90 cu. in. and as each cubic inch of iron weighs .26 lbs. we multiply 
the 90 by .26 which equals 23.40 lbs. 

Now let us assume that this block. Fig. 178, were to be made of 
lead. By referring to the table, page 219 you will note that the 
A\^eight of 1 cu. in. of lead, is given as .410 and the total weight of 
this block made of lead would be 90 x .41 = 36.90 lbs. 



1 



3C 



'^ 20 ^ 

Pig. 179 

Fig. 179 represents a cylinder or rod — 3'' in diameter by 20' in 
length. In order to find the cubical contents of this figure, we will 
proceed in exactly the same manner as in the case of the block and 
multiply the square inch area of one end by the total length, 20 ft. 

It will be seen that the end not being square or oblong, a length 
cannot be multiplied by a width in order to get the square inch area, 
therefore formulas or fixed rules have been calculated to assist us 
in these problems. These formulas have been worked out by the use 
of higher mathematics and the final condensed result is written d^ x 
.7854 = A, as explained on page 189. The letter d represents the 
diameter, which may be given in inches, yards, etc. The letter A 
represents the area. 

206 



The table given on page 192 shows the areas of circles for differ- 
ent diameters, and by referring to the table it will be seen that the 
area of a 3" circle is 7.0686 — this result having been obtained by 
multiplying 3 x 3 x .7854. In order to obtain the cubical contents of 
this rod we must multiply the area of one end by its length ; how- 
ever, the area obtained is given in square inches, therefore we must 
multiply this by its length in inches. Reduce the 20' to inches (20 x 
12= 240''), and the total operation for finding the cubical contents 
of this rod may be stated in the following condensed form: 

3 X 3 X .7854 x 240 = 1696.46 cu. in. 

The rules for finding the square inch area and the circumference 
of a circle, also the area of a triangle should be memorized as these 
are the most common — the others for various shaped surfaces may 
be referred to when needed. 

The method of finding the weight of the rod, Fig. 179, is ex- 
actly the same as that for the block — the cubical contents multiplied 
by the weight of 1 cu. in. of the material from which it is made. 
Assume this rod were to be made of aluminum,. by referring to the 
table you will note that 1 cu. in. of aluminum weighs .092 lbs. which, 
when multiplied by the total number of cubic inches in the rod 
(1696.46 cu. in.), is equal to 156 lbs. and the total operation may be 
stated 

1696.46 X .092 = 156 lbs. 



HOLLOW CYLINDER. 
(Cubic Inches in Walls) 

Let us figure the cubic inches in the walls of a hollow cylinder 
or pipe using the formula shown in Fig. 176 page 205, which reads 
V ^= (D2 — d^) X .7854 x h. Assume that the outside diameter is 12", 
inside diameter 9'' and the length 8'. Feet and inches cannot be mul- 
tiplied together so we must change the 8' to inches, by multiplying 
it by 12, which equals 96. The formula may be written : 

V = (122 — 92) X .7854 x 96, which reduced equals 

V = (144 — 81) X .7854 x 96. This is then written 

144 
—81 

63 

207 



V 



(63) X .7854 X 96, and equals 
63 

X .7854 



252 
315 
504 
441 

49.4802 
x96 

2968812 
4453218 



4750.0992 cu. in. of metal in pipe = V. 



ESTIMATING WEIGHT OF CASTING FROM PATTERN. 



The approximate weight of a casting may be obtained by multi- 
plying the weight of the pattern by the figure given in the table 
which corresponds to the material from which the pattern is made, 
and the material poured in the casting. Example : 

If a pattern is made of white pine, weight 10 lbs., and casting 
is to be made of cast iron, then multiply 10 x 14.7, (see table) which 
equals 147 lbs. — Aveight of casting. 

AlloAvance should be made for any metal in the pattern. 

^ Weight when cast in ^ 

Pattern weighing Cast Yellow Gun Aluminum 

one pound Iron Brass Metal 

Pounds. Pounds. Pounds. Pounds. 

Bay wood 8.8 9.9 10.3 3.2 

Beech 8.5 9.5 10.0 3.1 

Cedar 16.1 18.0 18.9 5.8 

Cherry 10.7 12.0 12.6 3.9 

Linden 12.0 13.5 14.1 4.3 

Mahogany 8.5 9.5 10.0 3.1 

Maple 9.2 10.3 10.8 3.2 

Oak 9.4 10.5 11.0 3.4 

Pear 10.9 12.2 12.8 3.9 

Pine, white 14.7 16.5 17.3 5.3 

Pine, yellow. 13.1 14.7 15.4 4.7 

Whitewood 16.4 18.4 19.3 5.9 

Foundry Data Sheets 

208 



If pattern has cores, the approximate weight of casting may be 
determined as follows : 

Fill the core boxes with dry sand — weigh the sand and multiply 
by one of the following factors : 

4.0 if cast in iron, 

4.65 if cast in brass or gun metal, 

1.39 if cast in aluminum. 

Then subtract this product from the weight obtained when the 
solid pattern was multiplied by the factor corresponding to the ma- 
terial in which it was cast. Example : 

Assume the total weight of casting when estimated from solid 
pattern, was 147 lbs., as mentioned; the sand which filled the core 
boxes weighed 12 lbs ; casting being made of cast iron — 12 lbs. x 4 
(factor for cast iron) equals 48 lbs. 

147 

—48 



99 lbs. net weight of casting. 




EXAMINATION 
LESSON 20 

1. Fig. 154. If b = 8 and h = 10, what is the area of this figure ? 

2. Fig. 158. If r = 12, what is the area of this figure ? 

3. Fig. 174. If d =^- 6 and h = 14, what is the volume of this figure ? 



209 



LESSON TWENTY-ONE 



METHOD OF ESTIMATING THE WEIGHT OF A CASTING FROM 

DRAWING. 

Fig. 180. When it is desired to estimate the weight of a casting, 
it is customary to resolve the object into several distinct geometrical 
figures and in this case we have 

(1) A cone 4" diameter at its base and 2^' high, 

(2) A cylinder 4" outside diameter, 3" inside diameter and 

51/2" long, 

(3) A flat plate or base 6 x 6 x y^" thick with a 3" hole thru its 

center, 

(4) 4 triangular ribs 1 x 1 x ^" thick. 

We will now explain how to find the cubical contents of each 
part : 

The Cone : — By referring to page 204 we see that the formula for 
finding the cubical contents (or volume) is 

h 

V = d2 X .7854 X — 

3 

Inserting the figures representing the diameter and height of 
the cone, we have 

2 2 
V =r 42 X .7854 X — V = 16 X .7854 x — 

3 3 

16 

.7854 



64 

80 
128 
112 



2 25.1328 

12.5664 X — = = 8.3776 cu. in. 

3 3 

211 







The square inch area of walls of a hollow cylinder is equal to the 
area of the inner circle subtracted from the area of the outer circle. 
As the areas of various circles have been worked out, they may be 
used instead of the formulas for the hollow cylinder, Fig. 176. It is 
to be remembered that the end area of the cylinder must be multi- 
plied by its length. 

The Cylinder: — By referring to the areas of circles on page 192 
it will be seen that the area of a 4" circle is 12.566 and a Z" circle is 
7.068 — the difference in these two areas Avill be the square inch area 
of one end of the cylinder. This multiplied by the length (5.5) will 
equal the cubic inches in the cylinder, and the complete operation 
will be written : 

12.56 
—7.06 



5.50 net area of one end. 
x5.5 length. 



2750 
2750 

30.25 cu. in. — cubical contents of cylinder. 

Flat Plate: — 6 x 6 x i/^" equals the cubical contents of the flat 
plate, but it will be seen that this plate has a V hole thru its center 
and also that the four corners are rounded with i/^'' radius. Subtract 
the cubical contents of this 3" hole. It is customary to ignore the 
loss of the cubical contents caused by the %" radius. 

212 



6x6 = 36 sq. in. Subtracting the area of a 3" hole (see page 192) 
36. 

7.068 



28.932 sq. in. area 3" hole (multiplying this by the thickness of %") 
X.5 



14.4660 cu. in. total in flat plate, minus hole. 

Ribs: — The square inch area of one rib is equal to 



base X height 1x1 1 

-, which is equal to = — or .5 



b h 



2 2 2 

.5 sq. in. As there are four ribs multiply by 4. 
4 



2.0 sq. in. These ribs being i/4" thick (.25) multiply by .25. 
.25 



100 
40 



.500 or a total of .5 cu. in. 

Total cubic inches in casting: 

Cone 8.377 

Cylinder 30.25 

Flat Plate 14.466 

Ribs .5 



53.593 cu. in. 

By referring to page 219, it will be seen that 1 cu. in. of east iron 
weighs .26 lbs. — there being 53.593 cu. in. in this casting, the total 
weight will be : • 

53.593 
X.26 



321558 
107186 

13.93418 lbs. 

218 



ESTIMATING THE WEIGHT OF CAST IRON FLYWHEEL 

SHOWN IN FIG. 181. 




7^«*-A?/ 



^£.CflOH-flB 



Rim. — There are two methods of finding the cubic inches in the 
rim ; first, the net area between the outside and the inside diameter 
(side view) multiplied by the width, 8". Example : 

Rim = 72" outside diameter 

60" inside diameter • ■ 

8" wide 



Area 72" circle 
Area 60" circle 

Area of side of rim 



= 4071.50 (see table, page 196) 
= 2827.43 



= 1244.07 sq. in. 

x8 



9952.56 cu. in. in rim. 

The second method is — find the area thru the cross section of the 
rim (6 X 8" = 48) and multiply this by the average circumference, 
which is 72 207.3456 

60 x48 



2 J 132 



^^^^ average 
X3.1416 


diameter 


396 
66 

264 

66 
198 




207.3456 average 
Either method may be 


circumference 
used. 

214 



16587648 
8293824 



9952.5888 cu. in. in rim. 



You will note there is a. small section around the inner circum- 
ference of the rim (see sectional view) which has the shape of one- 
half circle and is marked 1%" R — equal to 3" diameter. 

The area of ^ of a 3" circle is equal to 

7.0686 
= 3.5343 sq. in. 



The average circumference of this section is 183.78360" 

60" 
60 — 3 = 57 



117 



2 



= 581/2" diameter x 3.1416 = 



58.5 183.78 

X3.1416 x3.53 



3510 55134 

585 91890 

2340 55134 

585 



1755 648.7434 cu. in. half center 
— section 



183.78360 average circumference 

Hub: — Outside diameter at center 16" (Not taking into con- 
Diameter at edge 14" (sideration the i/^ cir- 

2 J 30" (cular section wliich is 

(around the hub 

Average outside diameter 15" (proper. 

Area of a 15" circle = 176.71 sq. in. 

xl2 width 



35342 
17671 



2120.52 cu. in. 



215 



However, the hub has a large hole thru the center, which is 7" in 
diameter and 12" long ; this must be deducted from the solid hub. 



ea of a 7" circle 


— 38.48 sq. in. 
xl2 


' 


7696 
3848 




461.76 cu. in. 

2120.52 
461.76 



1658.76 cu. in. in hub. 

Here again we have a half circle section around the outside of 
the hub — 2" radius or 4" diameter. The area of I/2 of 4" circle is 

12.56 
== 6.28. 



The average diameter of this section is 16 -|- 4 = 20" outside 

16" inside 
2 fW 

18" average 

diameter. The circumference for this diameter is equal to 56.54 (see 
table page 193). Multiplying this by the area of the half circular 
section, which is 6.28 sq. in. equals the cubic inches. 

56.54 
x6.28 



45232 
11308 
33924 



355.0712 cu. in. 

Arms: — The arms are oval in shape, and the average dimensions 
are as follows : 

6 3" 

7% 31/2 



2 J 131/2 2 J 6I/2 

6%" average length of sec. 3%" average width of section. 

See formula for the area of an oval section, Fig. 159, page 202. 

216 



A — 


.7854 X D X d 


. 


D — 


6% — 6.75 




d — 


31/4 — 3.25 


.7854 
x6.75 




39270 






54978 






47124 




5.301450 






x3.25 




265 






106 






159 



17.225 sq. in. area of arm. 

The length of an arm may be taken as being 

60 — 3 = 57" 
16 + 4 == 20 
2 J~37^ 



181/2" long. 



The area of the cross section of the arm multiplied by this length 
equals the cubic inches in one arm — 

17.22 

xl8.5 



8610 
13776 
1722 

318.570 



As there are six arms, multiply 318.57 

x6 



1911.42 cu. in. in the six arms. 
217 



Now total up all the cubic inches in the various sections, thus 
Eim 9952.58 

Cubic inches in % ring of 

inside diameter of rim 648.74 
Hub 1658.76 

Cubic inches in % ring on 

outside of hub 355.07 

6 arms 1911.42 



14526.57 cu. in. in fly wheel. 

X.26 weight of 1 cu. in. of cast iron. 



8715942 
2905314 



3776.9082 total weight of fly wheel in lbs. 

Note: — The majority of flywheels, pulleys, etc., will not have the 
half circular sections around the inside of the rim and the outside of 
the hub so pronounced, or in other words, they will be much flatter 
— in that case allowance may be made for these by increasing or 
decreasing the diameter. 



EXAMINATION 
LESSON 21 

1. Fig. 161. (a) If the fly wheel were made of steel, how much 

would it weigh? 

(b) If made of cast iron, what would be the weight of 
the rim, if it were 144 inches outside diameter and 
132 inches inside diameter x 8 inches wide? — 
Include half circular section on inside of rim, li/^ 
inch radius, in calculating. 



218 



LESSON TWENTY .TWO 



SPECIFIC GRAVITY. 

The specific gravity of a body is the ratio between its weight and 
the weight of a like volume displaced of distilled water at a temper- 
ature of 62° F. 

The specific gravity of a gas is the ratio between its weight and 
a like volume of air at 32° F. 

The weight of 1 cubic foot of distilled water at 62° F. is equal 
to 62.355 lbs. and the weight of 1 cubic foot of air at 32° F. is .08073 
lbs. 

In order to find the weight per cubic foot of any substance, 
knowing its specific gravity, it is necessary to multiply its specific 
gravity by 62.355 lbs. The weight of 1 cubic foot of any gas at 
atmospheric pressure and at 32°F. is found by multiplying its specific 
gravity by .08073 lbs. 

The specific gravity of water is taken as a unit of 1 for sub- 
stances ; and the specific gravity of air is taken as a unit of 1 for all 
gases. 

Specific W eiffht per 
Name of Substance Metals ^^^^^^^ ^^ i^ ^^^ 

Platinum, rolled 22.67 .818 

Platinum, wire 21.04 .759 

Gold 19.32 .697 

Mercury, at 60° F 13.58 .490 

Lead 11.37 .410 

Silver 10.53 .380 

Bismuth 9.80 .354 

Copper, pure 8.82 .318 

Bronze 8.85 .319 

Brass, common 8.50 .307 

Steel 7.80 .281 

Iron, wrot and rolled 7.85 .283 

Iron, cast 7.20 .260 

Tin, English 7.29 .263 

Zinc, rolled 7.15 .258 

Antimony 6.71 .242 

Aluminum 2.56 .092 

Foundry Dala Sheets 

219 



AVERAGE SPECIFIC GRAVITY OF MISCELLANEOUS 

SUBSTANCES. 

^ , , Specific Weight per 

Substance (.^^^i^y ^^ f^ 11^^ 

Asbestos 2.8 175 

Asphaltum 1.4 87 

Borax 1.75 109 

Brick, common -. 1.8 112 

Brick, fire 2.3 144 

Brick, hard 2.0 125 

Brick, pressed 2.15 134 

Brickwork, in mortar 1.6 100 

Brickwork, in cement 1.8 112 

Cement, Portland 3.1 194 

Chalk 2.6 163 

Charcoal .4 25 

Coal, anthracite 1.5 94 

Coal, bituminous 1.27 79 

Concrete 2.2 137 

Earth, loose 1.2 75 

Earth, rammed 1.6 100 

Emery 4.0 250 

Glass 2.6 163 

Granite 2.65 166 

Gravel 1.75 109 

Gypsum 2.2 137 

Ice 9 56 

Ivory 1.85 115 

Limestone 2.6 163 

Marble 2.7 "l69 

Masonry 2.4 150 

Mica 2.8 175 

Mortar 1.5 94 

Phosphorus 1.8 112 

Plaster of Paris 1.8 112 

Quartz 2.6 163 

Salt, common 2.1 131 

Sand, dry 1.6 100 

Sand, w^et 2.0 125 

Sandstone 2.3 144 

Slate 2.8 175 

Soapstone 2.7 169 

Soil, common black 2.0 125 

Sulphur 2.0 125 

Trapp 3.0 187 

Tile 1.8 112 

The w^eight per cubic foot is calculated on the basis of the spe- 
cific gravity, and considers the material solidly packed. With many 
substances this is practically impossible, and a cubic foot of ordinary 
anthracite coal, for example, does not weigh more than from 55 to 

65 lbs. due to the air spaces between the pieces of coal. 

220 



SPECIFIC GRAVITY AND AVERAGE WEIGHT PER CUBIC 



FOOT OF WOOD 

Specific 
Gravity- 
Beech 73 

Cedar 62 

Cherry 66 

Linden : .60 

Mahogany 81 

Maple 68 

Oak, white 77 

Oak, red. 74 

Pine, white .45 

Pine, yellow 61 

Walnut 75 

SPECIFIC GRAVITY OF GASES. 

(At 32° F.) 



Average weight 
per cubic foot 

46 lbs. 

39 lbs. 

41 lbs. 

37 lbs. 
51 lbs. 

42 lbs. 
48 lbs. 
46 lbs. 
28 lbs. 

38 lbs. 
38 lbs. 



Specific 
Gas Gravity 

Air 1.000 

Acetylene 910 

Alcohol vapor 1.601 

Ammonia 592 

Carbon dioxide 1.520 

Carbon monoxide 967 

Chlorine 2.423 

Ether vapor 2.586 

Ethylene 967 

Hydrofluoric acid 2.370 

Hydrochloric acid 1.261 



Specific 
Gas Gravity 

Hydrogen 069 

Illuminating gas 040 

Mercury vapor 6.940 

Marsh gas 555 

Nitrogen 971 

Nitric oxide 1.039 

Nitrous oxide 1.527 

Oxygen 1.106 

Sulphur dioxide ......... 2.250 

Water vapor 623 



1 cubic foot of air at 32° F. and atmospheric pressure weighs 
.0807 lbs. 

SPECIFIC GRAVITY OF LIQUIDS. 



Specific 
Liquid Gravity 

Acetic acid 1.06 

Alcohol, commercial 83 

Alcohol, pure 79 

Ammonia 89 

Benzine .69 

Bromine 2.97 

Carbolic acid 96 

Carbon disulphide 1.26 

Cotton-seed oil 93 

Ether, sulphuric 72 

Fluoric acid 1.50 

Gasoline 70 

Kerosene 80 

Linseed oil 94 

Mineral oil 92 



221 



Specific 
Liquid Gravity 

Muriatic acid 1.20 

Naphtha 76 

Nitric acid 1.22 

Olive oil .. .92 

Palm oil 97 

Petroleum oil 82 

Phosphoric acid 1.78 

Rape oil 92 

Sulphuric acid 1.84 

Tar 1.00 

Turpentine oil 87 

Vinegar 1.08 

Water 1.00 

Water, sea 1.03 

Whale oil 92 



^•iBDeiz^T''^"^* 






L 



<ii 







r"=> IS 2 
HOW TO READ ' ' U " GAUGES. 

Fig. 182 shows a "U" gauge and is used to determine the pres- 
sure caused by air or some other gas which may be confined under 
pressure or flowing thru a chamber. 

The gauge is read as follows : Rubber tubing connects one end of 
the tube to the chamber in which the gases are confined under pres- 
sure, or are flowing. A valve is generally placed between the U 
gauge and the chamber. When the valve is opened, the gas will 
flow into the gauge and cause the liquid which formerly stood level 
in both upright portions of the tube to rise in one and be loAvered 
in the other. (See Figure). By measuring the distance in inches 
between the high and low level, using an ordinary rule, and multi- 
plying this distance by .5774 when water is used, and by 7.859 when 
mercury is used, will give the ounce pressure per square inch. 

Tables have been compiled giving the resulting ounces for 
various heights in inches when either water or mercury is used. 

Ounces Pressure corresponding to different heights of water in 



''U" gauge. 














Ounces Pres- 




Ounces Pres- 




Ounces Pres 




sure Per 




sure Per 




sure Per 


Inches 


Square Inch 


Inches 


Square Inch 


Inches 


Square Inch 


1/2 




.2887 


7 


— 4.04 


16 


— 9.25 


1 




.5774 


71/2 


4.33 


18 


10.39 


2 




1.15 


8 


' . 4.62 


20 


11.54 


21/2 




1.44 


81/2 


4.90 


22 


12.70 


3 




1.73 


9 


5.19 


24 


13.86 


31/2 




2.02 


91/. 


5.48 


26 


15.00 


4 




2.31 


10 


5.77 


28 


16.16 


41/2 




2.59 


101/0 


6.06 


30 


17.32 


5 




2.88 


11 


6.35 


34 


19.63 


51/2 




3.17 


111/9 


6.64 


36 


20.78 


6 


- 


3.46 


12 


6.93 






61/2 




3.75 


14 


8.08 







222 



Corresponding to the different heights of mercury in "U" gauge 

Ounces Approximate 

Pressure Pounds 

per square inch per square inch 



Inches 



1 
2 



1/2 



'2 

3 

31/2 
4 

41/2 
5 

51/0 
6 

61/2 
7 

71/2 
8 

81/2 
9 

91/2 
10 



3.929 
7.859 
15.72 
19.647 
23.577 
27.50 
31.436 
35.36 
39.29 
43.22 
47.154 
51.083 
55.01 
58.94 
62.87 
66.80 
70.73 
74.66 
78.59 



1.47 

1.72 

1.97 

2.2 

2.46 

2.7 

2.94 

3.2 

3.43 

3.68 

3.92 

4.17 

4.42 

4.66 

4.92 



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O fZ34-S6ysS/0//^ 



CURVE OR GRAPH READINGS. 

A curve is the graphic representation of the results obtained 
from a series of tests, or the result of formulas or equations. Fig. 
183 is a curve representing the results of tests taken every minute 
during the refining period in the manufacture of steel by the con- 
verter process. 



223 



By the use of a curve properly made, it is convenient to read 
at a glance, much that would require considerable data and other 
printed matter to explain. Curves are made in great variety. The 
reading of complicated curves is generally explained. 

No doubt you know that steel and iron contain carbon. The 
curve in Fig. 183 shows the reduction of carbon for every minute 
of the blow in the manufacture of steel by the converter process. 
As will be noted at the bottom, the total time of blow is ten minutes. 
The liquid metal poured into the converter contained 3.50 carbon 
(see figures at left) ; after 8 minutes of blowing air thru or over the 
metal, the carbon in the liquid metal was reduced to about 2.15. 
The dotted line indicates the method of reading — first up from the 
8, then horizontally to the left. 



SHRINKAGE OF CASTINGS PER FOOT. 

Fractions Decimals 
Metals . of an inch of an inch 

Pure aluminum 13/64 .2031 

Nickel aluminum casting alloy 3/16 .1875 

"Special Casting Alloy," made by the 

Pittsburgh Reduction Co 11/64 .1718 

Iron, small cylinders 1/16 .0625 

Iron, pipes 1/8 .1250 

Iron, girders, beams, etc 1/64 .1000 

Iron, large cylinders, contraction of 

diameter at top 5/8 .6250 

Iron, large cylinders, contraction of 

diameter at bottom 5/64 .0830 

Iron, large cylinders, contraction in 

length 3/32 .0940 

Cast iron 1/8 .1250 

Steel 3/16 to 1/4 .1875 to .2500 

Malleable iron 1/8 .1250 

Tin 1/12 .0833 

Britannia 1/32 .03125 

Thin brass castings : . . . 11/64 .1670 

Thick brass castings 5/32 .1500 

Zinc 5/16 .3125 

Lead 5/16 .3125 

Copper 3/16 .1875 

Bismuth 5/32 .1563 

Semi-steel 1/8 .125 

The contraction of iron, semi-steel or steel will vary according to 
the difference in the percentage of metalloids ; for instance, high sil- 
icon will shrink less than low silicon, and vice versa. 



224 



CAPACITY OF CYLINDRICAL TANKS 

To find how many U. S. gallons a cylindrical tank will hold: 
Multiply the square of the inside diameter by 0.7854, which gives 
the area; multiply that result by the depth and this gives the 
cubic contents of the tank. If measurements are in inches, divide 
the cubic contents by 1728 and you then have contents expressed 
in cubic feet; then multiply by 7.4805 (U. S. gallons in each cubic 
foot of water) and the final result is the number of U. S. gallons 
the tank will contain. 

NUMBER OF GALLONS IN ROUND TANKS 



Length 

or 
Depth 








Diameter 


in Inches 




























in 
Feet 


18 
26 


24 


30 


36 


42 


48 


54 


60 


66 


72 


2 


47 


73 


105 


144 


188 


238 


294 


356 


424 


2^A 


33 


59 


90 


131 


180 


235 


298 


367 


445 


530 


3 


40 


71 


109 


157 


216 


282 


357 


440 


534 


636 


3H 


47 


83 


127 


183 


252 


329 


416 


513 


623 


742 


4 


54 


95 


145 


209 


288 


376 


475 


586 


712 


848 


4H 


61 


107 


163 


235 


324 


423 


534 


659 


801 


954 


5 


68 


119 


180 


261 


360 


470 


593 


732 


890 


1060 


5H 


75 


131 


200 


287 


396 


517 


652 


805 


979 


1166 


6 


82 


143 


217 


313 


432 


564 


711 


878 


1068 


1272 


W2 


89 


155 


235 


339 


468 


611 


770 


951 


1157 


1378 


7 


96 


167 


253 


365 


504 


658 


829 


1024 


1246 


1484 


7H 


103 


179 


271 


391 


540 


705 


888 


1097 


1335 


1590 


8 


110 


191 


289 


417 


576 


752 


947 


1170 


1424 


1696 


8H 




203 


307 


443 


612 


799 


1006 


1243 


1513 


1802 


10 




239 


361 


521 


720 


940 


1183 


1462 


1780 


2120 


12 




287 


433 


625 


864 


1128 


1419 


1754 


2136 


2544 


14 










1008 


1316 


1655 


2046 


2492 


2968 


16 










1152 


1504 


1891 


2338 


2848 


3392 


18 














2127 


2630 


3204 


3816 


20 















2363 


2922 


3560 


4240 













DIAMETER 


IN FEET. 












8 


9 


10 


1 


12 


13 


14 


15 


16 


18 


20 


22 


5 


1,875 


2,380 


2,925 


3,550 


4,237 


4,960 


5,765 


6,698 


7,520 


9,516 


11,750 


14,215 


6 


2,250 


2,855 


3,510 


4,260 


5,084 


5,952 


6,91JB 


8,038 


9,024 


11,419 


14,100 


17,059 


\ 


2,625 


3,330 


4,095 


4,970 


5,931 


6,944 


8,071 


9,378 


10,528 


13,322 


16,450 


19,902 


8 


3,000 


3,805 


4,680 


5,680 


6,778 


7,936 


9,224 


10,718 


12,032 


15,225 


18,800 


22,745 


9 


3,375 


4,280 


5,265 


6,390 


7,625 


8,928 


10,377 


12,058 


13,536 


17,128 


21,150 


25,588 


10 


3,750 


4,755 


5,850 


7,100 


8,472 


9.92P 


11,530 


13,398 


15,040 


19,031 


23,500 


28,431 


11 


4,125 


5,250 


6,435 


7,810 


9,319 


10,913 


12,083 


14,738 


16,544 


20,934 


25,850 


31,274 


12 


4,500 


5,705 


7,020 


8,520 


10,166 


11,904 


13,836 


16,078 


18,048 


22,837 


28,200 


34,117 


13 


4,875 


6,180 


7,605 


9,230 


11,013 


12,896 


14,989 


17,418 


19,552 


24,740 


30,550 


36,960 


14 


5,250 


6,655 


8,190 


9,940 


11,860 


13,888 


16,142 


18,758 


21,056 


26,643 


32,900 


39,803 


15 


5,625 


7,130 


8,775 


10,650 


12,707 


14,880 


17,295 


20,098 


22,260 


28,546 


35,250 


42.646 


16 


6,000 


7,605 


9,360 


11,360 


13,554 


15,872 


18,448 


21,438 


24,064 


30,449 


37,600 


45,489 


17 


6,375 


8,080 


9,945 


12,070 


14,401 


16,864 


19,601 


22,778 


25,568 


32,352 


39,950 


48,332 


18 


6,750 


8,535 


10,530 


12,780 


15,248 


17,856 


20,754 


24,118 


27,072 


34,255 


42,300 


51,175 


19 


7,125 


9,010 


11,115 


13,490 


16,095 


18,848 


21,907 


25,458 


28,576 


36,158 


44,650 


54,018 


20 


7,500 


9,490 


11,700 


14,200 


16,942 


19,840 


23,060 


26,798 


30,080 


38,062 


47,000 


56,861 



225 



BOARD FEET IN PATTERN LUMBER. 

The accompanying table, which gives the number of board feet 
in planks of various sizes, will be found of value to pattern makers 
and others in calculating the cost of lumber for patterns and flasks. 
The size of the pieces is. given at the left and their length in the 
various columns across the top of the table. 

A board foot contains 144 cubic inches of lumber; that is, a 
plank 12" square and 1" thick contains 1 board foot; if it were 2 
inches thick, it would contain 2 board feet. However, in selling lum- 
ber, dealers always figure boards less than 1" thick as if they were 
inch boards. 











Length in Feet. 












Size. 


4 


5 


6 


7 8 9 10 11 
Feet Board Measure. 


12 


13 


14 


15 


16 


1 X 1 


0.33 


0.41 


0.5 


0.58 0.66 0.75 0.83 0.91 


1.00 


1.08 


1.16 


1.25 


1.33 


1 X 2 


0.66 


0.82 


1.0 


1.16 1.32 1.50 1.66 1.82 


2.00 


2.16 


2.32 


2.50 


2.66 


1 X 3 


1.00 


1.25 


1.5 


1.75 2.00 2.25 2.50 2.75 


3.00 


3.25 


3.50 


3.75 


4.00 



1 X 4 1.33 1.66 2.0 2.33 2.66 3.00 3.33 3.66 4.00 4.33 4.66 5.00 5.33 

1 X 5 1.66 2.08 2.5 2.91 3.33 3.75 4.16 4.58 5.00 5.41 5.83 6.25 6.66 

1 X 6 2.00 2.50 3.0 3.50 4.00 4.50 5.00 5.50 6.00 6.60 7.00 7.50 8.00 

1 X 7 2.33 2.91 3.5 4.08 4.66 5.25 5.81 6.37 7.00 7.57 8.16 8.75 9.33 

1 X 8 2.66 3.33 4.0 4.66 5.33 6-00 6.66 7.33 8.00 .8.66 9.33 10.00 10.66 

1 X 9 3.00 3.75 4.5 5.25 6.00 6.75 7.50 8.25 9.00 9.75 10.50 11.25 12.00 

1 X 10 3.33 4.16 5.0 5.83 6.66 7.50 8.33 9.16 10.00 10.82 11.66 12.50 13.33 

1 xll 3.66 4.58 5.5 6.4-1 7.33 8.25 9.16 10.08 11.00 11.90 12.82 13.75 14.66 

1 X 12 4.00 5.00 6.0 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.00 



VA 


X 


I 0.41 


0.52 


0.62 


0.73 


0.83 


0.93 


1.04 


1.14 


1.25 


1.35 


1.45 


1.56 


1.66 


Wa 


X 


2 0.83 


1.04 


1.25 


1.45 


1.66 


1.87 


2.08 


2.28 


2.50 


2.70 


2.91 


3.12 


333 


\% 


X 


3 1.24 


1.56 


1.87 


2.18 


2.50 


2.81 


3.12 


3.43 


3.75 


4.05 


4.37 


4.68 


5.00 


Wa 


X 


4 1.66 


2.08 


2.50 


2.91 


3.32 


3.75 


4.16 


4.57 


5.00 


5.41 


5.82 


6.25 


6.66 



154 X 5 2.08 2.60 3.12 3.64 4.16 4.68 5.20 5.72 6.25 6.76 7.28 7.81 8.32 

1J4 X 6 2.50 3.12 3.75 4.37 5.00 5.62 6.25 6.87 7.50 8.10 8.75 9.37 10.00 

1J4 X 7 2.91 3.64 4.38 5.10 5.83 6.56 7.29 8.01 8.75 9.47 10.20 10.93 11.66 

1^x8 3.32 4.16 5.00 5.82 6.65 7.50 8.32 9.15 10.00 10.82 11.66 12.50 13.32 

1^4 X 9 3.75 4.66 5.62 6.56 7.50 8.43 9.37 10.29 11.25 12.18 13.12 14.05 15.00 

1^ xlO 4.16 5.20 6.25 7.27 8.33 9.57 10.30 11.54 12.50 13.52 14.55 15.62 16.64 

IVi, xU 4.58 5.72 6.87 8.01 9.17 10.31 11.45 12.60 13.75 14.88 16.03 17.18 18.35 

1J4 xl2 5.00 6.25 7.50 8.75 10.00 11.25 12.50 12.75 15.00 16.25 17.50 18.75 20.00 



\y2 


X 


1 


0.5 


0.61 


0.75 


0.87 


1.0 


1.12 


1.23 


1.36 


1.5 


1.62 


1.74 


1.87 


2.0 


\V2 


X 


2 


1.0 


1.23 


1.50 


1.74 


2.0 


2.25 


2.46 


2.73 


3.0 


3.24 


3.48 


3.75 


4.0 


V/z 


X 


3 


1.5 


1.84 


2.25 


2.61 


3.0 


3.37 


3.75 


4.13 


4.5 


4.86 


4.72 


5.62 


6.0 


IK 


X 


4 


2.0 


2.49 


3.00 


3.49 


4.0 


4.50 


4.99 


5.49 


6.0 


6.49 


6.99 


7.50 


8.0 


1/2 


X 


5 


2.5 


3.09 


3.75 


4.36 


5.0 


5.62 


6.18 


6.75 


7.5 


8.11 


8.73 


9.37 


10.0 


IK 


X 


6 


3.0 


3.75 


4.50 


5.25 


6.0 


6.75 


7.50 


8.25 


9.0 


9.75 


10.50 


11.25 


12.0 


IK 


X 


7 


3.5 


4.36 


5.25 


6.12 


7.0 


7.87 


8.72 


9.61 


10.5 


11.35 


12.24 


13.12 


140 


IK 


X 


8 


4.0 


5.00 


6.00 


7.00 


8.0 


9.00 


10.00 


11.00 


12.0 


13.00 


14.00 


15.00 


16.0 


IK 


X 


9 


4.5 


5.43 


6.75 


7.87 


9.0 


10.12 


11.25 


12.37 


13.5 


14.62 


15.74 


16.87 


18.0 


IK 


X 


10 


5.0 


6.24 


7.51 


8.73 


10.0 


11.25 


12.49 


13.74 


15.0 


16.23 


17.49 


18.75 


20.0 


IK 


X 


11 


5.5 


6.87 


8.25 


9.61 


11.0 


12.37 


13.74 


15.12 


16.5 


17.85 


19.23 


20.62 


22.0 


IK 


X 


12 


6.0 


7.50 


9.00 


10.50 


12.0 


13.50 


15.00 


16.50 


18.0 


19.50 


21.00 


22.50 


24.0 



Foundry Data Sheets 

226 



TABLE 

Showing the Number of Feet, Board Measure, contained In a 
Piece of Joist, Scantling or Timber of the Sizes given. 



Site In 


LENGTH IN FEET. 


bches. 


lO 


12 


14 


16 


18 


20 


22 


24 


26 


28 


30 


32 


2x 4 


6f 


8 


9i 


101 


12 


13} 


141 


16 


17} 


181 


20 


21} 


2x 6 


10 


12 


14 


16 


18 


20 


22 


24 


26 


28 


30 


32 


2x 8 


13^ 


16 


18f 


21i 


24 


261 


29} 


32 


341 


37} 


40 


421 

53; 


2x10 


16| 


20 


23i 


261 


30 


^H 


361 


40 


43} 


461 


50 


2x12 


20 


24 


28 


32 


36 


40 


44 


48 


52 


56 


60 


64 


2x14 


2H 


28 


32^ 


37} 


42 


461 


51} 


56 


601 


65} 


70 


74| 

85i 


2x16 


26§ 


32 


S7k 


421 


48 


53} 


581 


64 


69} 


741 


80 


3x 6 


15 


18 


21 


24 


27 


30 


33 


36 


39 


42 


45 


48 


3x 8 


20 


24 


28 


32 


36 


40 


44 


48 


52 


56 


60 


64 


3x10 


25 


30 


35 


40 


45 


50 


55 


60 


65 


70 


75 


80 


3x12 


30 


36 


42 


48 


54 


60 


66 


72 


78 


84 


90 


96 


3x14 


35 


42 


49 


56 


63 


70 


77 


84 


91 


98 


105 


112 


3x16 


40 


48 


56 


64 


72 


80 


88 


96 


104 


112 


120 


128 


4x 4 


13i 


16 


18f 


21} 


24 


261 


29} 


32 


341 


37} 


40 


42| 


4x 6 


20 


24 


28 


32 


36 


40 


44 


48 


SZ 


56 


60 


64 


4x 8 


26f 


32 


37i 


421 


48 


53} 


581 


64 


69} 


741 


80 


85i 
106| 


4x10 


SS^ 


40 


461 


53} 


60 


661 


73} 


80 


861 


93} 


100 


4x12 


40 


48 


56 


64 


72 


80 


88 


96 


104 


112 


120 


128 


4x14 


46f 


56 


65i 


741 


84 


93} 


1021 


112 


121} 


1301 


140 


149} 


6x 6 


30 


36 


42 


48 


54 


60 


66 


72 


78 


84 


90 


96 


6x 8 


40 


48 


56 


64 


72 


80 


88 


96 


104 


112 


120 


128 


6x10 


50 


60 


70 


80 


90 


100 


110 


120 


130 


140 


150 


160 


6x12 


60 


72 


84 


96 


108 


120 


132 


144 


156 


168 


180 


192 


6x14 


70 


84 


98 


112 


126 


140 


154 


168 


182 


196 


210 


224 


6x16 


80 


96 


112 


128 


144 


160 


176 


192 


208 


224 


240 


256 


8x 8 


531 


64 


74f 


85} 


96 


1061 


117} 


128 


138f 


149} 


160 


170| 


8x10 


66f 


80 


93} 


1061 


120 


133} 


1461 


160 


173} 


1861 


200 


213} 


8x12 


80 


96 


112 


128 


144 


160 


176 


192 


2C8 


224 


240 


256 


8x14 


931 


112 


1301 


149} 


168 


1861 


205} 


224 


242| 


261} 


280 


298| 


10x10 


83i 


100 


1161 


133} 


150 


1661 


183} 


200 


2161 


233} 


250 


266 


10x12 


100 


120 


140 


160 


180 


200 


220 


240 


260 


280 


300 


320 


10x14 


116^ 


140 


163} 


186f 
213} 


210 


233} 


2561 
293} 


280 


303} 


326f 


350 


373} 


10x16 


133i 


160 


1861 


240 


2661 


320 


3461 


373} 


400 


4261 


12x12 


120 


144 


168 


192 


216 


240 


264 


288 


312 


336 


360 


384 


12x14 


140 


168 


196 


224 


252 


280 


308 


336 


364 


392 


420 


448 


12x16 


160 


192 


224 


256 


288 


320 


352 


384 


416 


448 


480 


512 


14x14 


163| 
1861 


196 


2281 


261} 


294 


326f 
373} 


359} 


392 


424f 


457} 


490 


522| 


14x16 


224 


261} 


298' 


336 


410i 


448 


485} 


5221 


560 


597^ 



227 



GENERAL INFORMATION ABOUT FIRE BRICK. 

All fire brick should be kept in a dry place. 

Moisture, especially in cold weather, will greatly injure any 
brick. 

To obtain the best results from brickwork, observe the following 
precautions : 

Use good fire clay equal in refractoriness to the brick itself, 
mixing with water to thin soup. Dip brick and rub to make a brick 
to brick joint. 

Warm slowly to expel moisture. 

Bear in mind that fire clay brick contract, and silica, chrome and 
magnesia brick expand under high temperatures. 

Sudden variations of temperature cause silica brick to spall, and 
also reduce their refractoriness. All furnaces in which silica brick 
are used should therefore be heated up and cooled down slowly and 
uniformly. 

From 250 to 350 pounds of fire clay or silica cement are enough 
to lay one thousand brick. Fine ground fire clay should be used for 
laying fire clay brick, silica cement for silica brick, magnesia cement 
for magnesia brick, and chrome cement for chrome brick. 

For estimating on fire brick work, use the following figures : 

1 square foot 4V2-iiich wall requires 7 brick, 

1 square foot 9-inch wall requires 14 brick, 

1 square foot 13%-inch wall requires 21 brick, 

1 cubic foot brickwork requires 17 nine-inch straight brick, 

1 cubic foot fire clay brickwork weighs 150 pounds, 

1 cubic foot silica brickwork weighs 130 pounds, 

1,000 brick (closely stacked) occupy 56 cubic feet, 

1,000 brick (loosely stacked) occupy 72 cubic feet. 

For estimating on red brickwork, figure on nine cubic feet of sand 
and three bushels of lime for laying 1,000 brick. 



228 



REFRACTORY BRICKS 

Sizes and Shapes 

In order to eliminate as much labor as possible in the laying of 
refractory bricks for ovens, furnaces, kilns, etc., the manufacturers 
have made special shapes. These have been standardized and the 
names, sizes and shapes of the most common are here shown. 

Some manufacturers make special shapes in addition to those 
illustrated and are also in a position to make any shape required 
from drawings submitted by customers. 



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229 




EXAMINATION 
LESSON 22 

1. The specific gravity of ice is .9, how would you .find its weight 
per cubic foot? 

2. Fig. 182. If the distance between the high and low level is 10% 
inches, what would the pressure be if water were used in the 
tube 9 

3. How many gallons are there in a tank 5 feet in diameter x 20 
feet long? 

4. How many board feet in a 6 x 8 inch timber 20 feet long? 




280 



LESSON TWENTY-THREE 



SAFE LOADS FOR ROPES AND CHAINS. 

The following table was prepared by the National Founder's As- 
sociation and published in Industrial Engineering September 1914. 
It shows the safe loads that can be carried by wire rope, crane chain 
and I^Ianila rope of the sizes given when used in the positions and 
combinations shown. The loads in the table are lower than those 
usually specified, in order to insure absolute safety. When handling 
molten metal, the ropes and chains should be 25 per cent stronger 
than the figures in the table. 



Safe Loads for Ropes and Chains. 



Note. The safe loads in 
table are for each Single 
rope or chain. When used 
double or in other multiples 
the loads may be increased 
proportionately. 



PLOW Steel Wire 
Rope. 

[6 strands of 1 9 or 
37 wires.] 

If crucible steel rope 
is used reduce loads 
one-fifth. 



Dia. 
In. 

3/8 

1/2 

5/8 
3/4 

7/8 
1 

1 1/8 
1 1/4 
13/8 

n/2 



When Used 
Straight. 



Lb. 
1,500 

2,400 

4,000 

6,000 

8,000 

10,000 

13,000 

16.000 

19,000 

22,000 



When Used 

at 60° 

Angle. 




Lb. 

1,275 

2,050 

3,400 

5,100 

6,800 

8,500 

11,000 

13,500 

16,000 

19,000 



When Used 

at 45° 

Angle. 



Z\ 



Lb. 

1,050 

1,700 

2,800 

4,200 

5,600 

7,000 

9,000 

11,000 

13,000 

16,000 



When Used 
at 30° 
Angle. 




Lb. 

750 
1,200 
2,000 
3,000 
4,000 
5,000 
6,500 
8,000 
9,500 
11,000 



Crane Chain. 

* [Best grade of 
wrought iron, hand- 
made, tested, short- 
link chain.] 



1/4 
3/8 
1/2 
5/8 
3/4 

7/8 

1/8 

1/4 
13/8 



.1 

I' 
^1 



600 

1,200 

2,400 

4,000 

5,500 

7,500 

9,500 

12,000 

15,000 

22,000 



500 

1,025 

2,050 

3,400 

4,700 

6,400 

8,000 

10,200 

12,750 

19,000 



425 

850 

1,700 

2,800 

3,900 

5,200 

6,600 

8,400 

10,500 

16,000 



300 
600 
1,200 
2,000 
2,750 
3,700 
4,700 
6,000 
7,500 
11,000 



Manila Rope. 



[Best long fibre 
grade.] 



Dia. 


Cir. 


In. 


In. 


3/8 


1 


1/2 


11/2 


5/8 


2 


3/4 


21/4 


7/8 


23/4 


1 


3 


11/8 


3 1/2 


11/4 


3 3/4 


11/2 


4 1/2 


13/4' 


5 1/2 


2 


6 


21/2 


71/2 


3 


9 



120 

250 

360 

520 

620 

750 

1,000 

1,200 

1,600 

2,100 

2,800 

4,000 

6,000 



100 

210 

300 

440 

520 

625 

850 

1,025 

1,350 

1,800 

2,400 

3,400 

5,100 



85 

175 

250 

360 

420 

525 

700 

850 

1,100 

1,500 

2,000 

2,800 

4,200 



60 

125 

180 

260 

300 

375 

500 

600 

800 

1,050 

1,400 

2,000 

3,000 



281 



USE5UL INK)RMATION GIVING THE HEAT UNITS, WEIGHT 
PER CUBIC ?00T AND SPACE OCCUPIED BY VARIOUS FUELS. 

The unit of heat generally used for practical purposes 
is knoym as the British Thermal Unit (B,T,U,) and represents 
the amount of heat required to raise 1 lb, of water 1° F,, 
when at a temperature of 60° P. Its mechanical equivalent 
is 772 foot-pounds. A comparison of the heat values of 
various fuels is made in the following table: 

Heat Value in 
Fuels B.T.U'B per lb. 

Anthracite coal ••• 12,900 to 14,800 

Acetylene gas 20,700 

Bituminous coal 12,500 to 16,200 

Charcoal 13,700 

Coke 12,000 to 14.500 

Carbon, complete combustion . 14,500 

Coal gas 19,850 

Peat 7,400 to 10,200 

Wood 4,800 to 7,800 

Natural gas 22,000 

The thermal value of any fuel will vary l,ccording to 
the amount of moisture contained therein. 

Weight Cu. Ft. Storage 
Fuel lbs, per Space per ton 

cu.ft. of 2240 lbs. 



Anthracite coal, market size, 

piled loosely , 

Bituminous coal, broken, 

piled loosely . 

Dry coke 

Powdered coal 



52 to 56 

47 to 52 
23 to 32 
38 to 45 



40 to 43 

43 to 48 

80 to 97 



B.T.U. Pounds 

Kind . per lb. per gal. 

Fuel oil (residium of petroleum) 19 ,000 7,3 

Beaumont crude petroleum . . . ,19,060 7,5 

California crude petroleum . . 19,500 7.6 

Lima crude jpetroleum 18,820 7.5 

Pennsylvania crude petroleum . 18,940 7.5 

Kerosene 16,120 7,2 

Gasoline 14,200 5,9 

Denaturized alcohol . , . . . 13,140 5,7 

Alcohol (90 per cent) .... 10,080 5.6 

Coal tar 16,260 10.0 

Oil tar 16,970 9,5 

One barrel of oil contains 42 gallons. 



B.T,U, 
per gal, 

138,700 

142,950 

147,200 

141,150 

142,050 

116,000 

83,780 

74,900 

56,500 

162,600 

161.200 



233 



APPROXIMATE WEIGHT IN POUNDS OP SqUAHE AND ROUND 
CAST IRON PLATES 1 INCH THICK. 



SIZE 


D 


O 


SIZE 


D 


o 


SIZE 


D 


o 


12" 


37i 


29i 


61" 


.970 


762 


110" 


3154 


2477 


13 


44 


35 


62 


1002 


787 


111 


3212 


2523 


14 


51 


40 


63 


1035 


813 


112 


3270 


2568 


15 


58 i 

66i 


46 


64 


1068 


838 


113 


3329 


2614 


16 


52 


65 


1101 


865 


114 


3388 


2661 


17 


75 


59 


66 


1136 


892 


115 


3448 


2708 


18 


84 


66 


67 


1170 


919 


116 


3908 


2755 


19 


95 


74 


68 


1205 


945 


117 


3569 


2803 


20 


104 


82 


69 


1241 


997 


118 


3630 


2851 


21 


115 


90 


70 


1277 


1003 


119 


3692 


2900 


22 


126 


99 


71 


1314 


1032 


120 


3754 


2948 


23 


138 


108 


72 


1352 


1061 


i21 


3817 


2998 


24 


150 


118 


73 


1389 


1091 


122 


3880 


3047 


25 


163 


129 


74 


1428 


1122 


123 


3944 


3098 


26 


176 


139 


75 


1467 


1153 


124 


4009 


3148 


27 


190 


149 


76 


1506 


1183 


125 


4073 


3199 


28 


204 


160 


77 


1546 


1214 


126 


4139 


3251 


29 


219 


172 


78 


1586 


1246 


127 


4205 


3302 


30 


235 


185 


79 


1627 


1278 


128 


4271 


3355 


31 


251 


197 


80 


1668 


1210 


129 


4338 


3407 


32 


267 


210 


81 


1711 


1343 


130 


4406 


3460 


33 


284 


223 


82 


1755 


1377 


131 


4474 


3514 


34 


301 


237 


83 


1796 


1410 


132 


4542 


3567 


35 


319 


251 


84 


1839 


1445 


133 


461J2 


3623 


36 


338 


266 


85 


1884 


1479 


134 


4681 


3676 


37 


357 


280 


86 


1928 


1515 


135 


4751 


3731 


38 


376 


296 


^7 


1973 


1550 


136 


4822 


3787 


39 


397 


311 


88 


2019 


1586 


137 


4893 


3843 


40 


*417 


327 


89 


2065 


1622 


138 


4965 


3899 


41 


438 


344 


90 


2112 


1658 


139 


5037 


3956 


42 


459 


361 


91 


2159 


1696 


140 


5110 


4014 


43 


482 


379 


92 


2207 


1733 


141 


5183 


4071 


44 


505 


396 


93 


2255 


1772 


142 


5257 


4128 


45 


528 


415 


94 


2304 


1809 


143 


5331 


4187 


46 


552 


434 


95 


2353 


1848 


144 


5406 


4246 


47 


576 


453 


96 


2403 


1887 








48 


601 


472 


97 


2453 


1927 








49 


626 


491 


98 


2504 


1967 








50 


652 


512 


99 


2555 


2007 








51 


678 


533 


100 


2607 


2048 








52 


705 


553 


101 


2659 


2088 








53 


732 


575 


102 


2712 


2130 








54 


760 


597 


103 


2766 


2172 








55 


789 


620 


104 


2820 


2215 








56 


818 


642 


105 


2874 


2257 








57 


847 


665 


106 


2929 


2300 








58 


876 


689 


107 


2985 


2344 








59 


907 


713 


108 


3041 


2388 








60 


939 


737 


109 


3097 


2433 









233 



WEIGHTS OF ROUND AND SQUARE STEEL. 

Estimated weight per lineal foot. One cubic foot of steel weighs 490 lbs. 



Sizes 


• 


m 


Sizes 


• 


■ 


Sizes 


• 


m 


in 


Weight' 


Weight 


in 


Weight 
in Lbs. 


Weight 


in 


Weight 


Weight 


Inches. 


in Lbs. 


in Lbe. 


Inches 


in Lbe. 


Inches 


in Lbs. 


in Lbs. 


A 


.010 


.013 


4A 


44.07 


56.11 


8A 


173.6 


221.0 


y» 


.042 


.053 


m 


45.44 


57.85 


m 


176.3 


'224.5 




.094 


.119 


4A 


46.83 


59.62 


8A 


179.0 


228.0 


H 


.167 


.212 


iH 


48.24 


61.41 


8M 


181.8 


231.4 


^ 


.261 


:333 


4A 


49.66 


63.23 


»A 


184.5 


234.9 


^ 


.375 


.478 


m 


51.11 


65.08 


8H 


187.3 


238 5 


■A 


.511 


.651 


4A 


62.58 


66.95 


8A 


190.1 


242.0 


■,H ■ 


.667 


.850 


i'A 


54.07 


68.85 


84 


193.0 


245.6 




.845 


1.076 


4A 


55 59 


70.78 


8A 


195.7 


249:3 


Ps 


1.043 


.1.328 


m 


57.12 


72.73 


m 


198.7 


252:9 


1 


1.262 


I 608 


4ii 


58 67 


74.70 


8H 


201.6 


256.6 


1.502 


1.913 


4H 


60.25 


76.71 


8^ 


204.4 


260.3 


H 


1.773 


2.245 


m 


61.84 


78.74 


8ti 

m 


207.4 


264.1 


k 


2.044 


2.603 


m 


63.46 


80 81 


210.3 


267.9 


H 


2.347 


2.989 


4H 


65.10 


82.89 


m 


213 3 


271.6 


1 


2.670 


3.400 


5. 

5A 


66.76 


85.00 


9 


216.3 


275.4 


lik 


3.014 


3.838 


68.44 


87.14 


9A 


219.3 


279.3 


m 


3.379 


4.303 


5H 


70.14 


89.30 


QH 


222.4 


283.2 
28?. 


lA 


3.766 


4.795 


oA 


71.86 


91.49 


9A 


225.4 


IH 


4.173 


5.312 


5K 


73.60 


93.12 


9K 


228.5 


290.9 


» A 


4.600 


5.857 


5A 


75 37 


95.96 


9A 


23f.5 


2949 


m 


5.049 


6.428 


oVi 


77.15 


98.23 


9^-8 


234.7 


298.9 


lA 


5.518 


7.026 


5k 


78.95 


100.5 


9A 


237.9 


302.8 


IKa 


6.008 


7.650 


80 77 


102.8 


94 


241.0 


306.8 


lA 


6.520 


8.301 


5A 


82.62 


105.2 


9A 


244.2 


31Q.9 


'IH 


7.051 


8.978 


55'g 


84.49 


107.6 


m 


247.4 


315.0 


iH 


7.604 


9.682 


5!4 


86.38 


110.0 


9}| 


250.6 


319.1 


m 


8.178 


10.41 


oH 


88.29 


112.4 


9^ 


253.9 


323.2 


m 


8.773 


11.17 


5Ii 


90.22 


114.9 


m 


257.1 


327.4 


1} 


9.388 


11.95 


51- 


92.17 


117.4 
119.9 


9? 


260.4 


331 6 


iii 


10JS2 


12 76 


5ii 


94.14 


9{| 


263.7 


335.8 


2 


10.68 


13.60 


6 


96.14 


122.4 


10 


267.0 


340.0 


/A 


11.36 


14.46 


6A 


98.14 


125.0 


lOA 


270.4 


344.3 


2^ 


12.06 


15.35 


6Vs 


100.2 


127.6 


104 


273.8 


348.5 


2A- 


12J8 


16.27 


6A 


102.2 


130.2 


lOA 


277.1 


352.9 


■i'A 


13 52 


17.22 


6J4 


104.3 


132.8 


\m 


280.6 


357.2 


.»A 


14.28 


18.19 


6A 


106.4 


135.5 


lOA 


284.0 


361.6 


2H 


15.07 


19.18 


6H 


108.5 


138.2 


10^!^ 


287.4 


366.0 


2A 


15.86 


20.20 


6A 


110.7 


140.9 


lOA, 


290.9 


370.4 


2.4 


16 69 


21.25 1 


64 


112.8 


143.6 


10^2 


294.4 


3^74.9 


2A 


17.53 


22.33 i 


6A 


114 9 


146.5 


lOA 


297.9 


379.4 


•->5^ 


18.40 


23.43 1 


6H 


117.2 


149.2 • 
152.1 


105/8 


301.4 


383.8 


-'H 


19.29 


24.58 1 


6|i 


119.4 


10ft 


3(15.0 


388.3 


25i 


20.20 


25.00 


&H 


121.7 


154 9 


mi 


308.6 


392.0 


2H 


21.12 


26.90 


6H 


123.9 


157.8 


mi 


312.2 


397.5 


-"8 


22.07 


28.10 


6^8 


126.2 


160.8 


104 


315.8 


402.1 


>}l 


23.04 


29.34 


6H 


128.5 


163.6 


mi 


319.5 


406.8 


:} 


24.03 


30.60 


7 


130.9 


166.6 


11 


323.1 


411.4 


3A 


25.04 


31.89 


7A 


133.2 


169.6 


iiA 


326.8 


416.1 


iH 


26.08 


33.20 


IVb 


135.6 


173.6 


113^ 


330.5 


420.9 




27.13 


34.55 


7A 


137.9 


176.6 


iiA 


334.3 


425.5 


m 


28.20 


35.92 1 


7Ji 


140.4 


178.7 


nv4. 


337.9 


430.3 


3 A 


29.30 


37.31 : 


7A 


142.8 


181.8 


UA 


341.7 


435.1 


w» 


30.42 


38.73 


1% 


145.3 


184.9 


11^ 


345.5 


439.9 


3A 


31.56 


40.18 


7A 


147.7 


188.1 


llA 


349.4 


444.8 


3,4 


32.71 


41 65 


74 


150.2 


191.3 


IVA 


353.1 


449.6 


3A 


33.90 


43.14 


7A 


152.7 


194.4 


HA 


357.0 


454.5 


3ll 


35.09 


44.68 


m 


155.2 


197.7 


1111 


360.9 


459.5 


3U 


36.31 


^6.24 


7fi 


157.8 


200.9 


364.8 


464,4 


3^4 


37.56 


47.82 


1% 


160.3 


204.2 


UH 


368.6 


469.4 


3H 


38.81 


49.42 


m 


163.0 


207.6 


IIH 


372,6 


474,4 


3H 


40.10 


51.05 


V4 


165.6 


210.8 


UVs 


376.6 


479.5 


3.4 


41.40 


52.71 


711 


168.2 


214.2 


iHi 


380.6 


484.6 


4 


42.73 


54.40 


8 


171.0 


217.6 









HOW TO USE THE FOREGOING TABLE FOR CAST IRON. 

When this table is used for estimating cast iron, multiply the 
weight given for the size required by .92, which will equal the ap- 
proximate weight when made of cast iron. 



234 



Example: A 4'' square bar 12" long weighs 54.40 lbs., when made 
of steel (see table), multiply this weight by .92 and the weight o:^ 
a cast iron bar this size will be 50 lbs. 

54.40 
X.92 



10880 
48960 



50.0480 lbs. 
Assume cast iron to weigh 450 lbs. per eu. ft. 




EXAMINATION 
LESSON 23 

1. What is the weight of a piece of cast iron 30x30 x 18 inches? 

2. What is the weight of a round steel bar 71/2 inches in diameter 
and 18 inches long? See table. 

3. What is the approximate weight of the above bar if made of 
cast iron? 



% 



235 



LESSON TWENTY-FOUR 



THERMOMETER SCALES. 

There are three thermometer scales in general use. 

The Fahrenheit (F.), which is generally used in English speaking 
countries ; 

The Centigrade (C.) or Celsius, which is used in several con- 
tinental countries and in scientific work ; 

The Reaumur (R.)j which is used to some extent on the European 
continent, notably in Germany. 

In the Fahrenheit thermometer, the freezing point of water is 
marked at 32° on the scale and the boiling point, at atmospheric 
pressure, at 212°. The distance between these two points is divided 
into 180°. On the Centigrade scale, the freezing point of water is 
at 0° and the boiling point at 100°. On the Reaumur scale, the 
freezing point is at 0° and the boiling point at 80°. The following 
formulas may be used for converting temperatures given on any one 
of the scales to the other scales : 



9 X degrees C 9 x degrees R 
Degrees Fahrenheit = ^ 32 = + 32 



Degrees Centigrade = 



5 X (degrees F — 32) 5 x degrees R 



9 



4 X degrees C 4 x (degrees F — 32) 
Degrees Reaumur = = 



237 



TEMPERATURES 



Degrees Fahrenheit 




De 


2rrees ( 


[Centigrade 


and Corresponding Centigrade 


and Corresponding Fahrenheit 


F. 


C. 


F. 


C. 


F. 


C. 


C. 


F. 


C. 


F. 


C. 


F. 


32 


1040 560 


1740 


949 


32 


520 


968 


860 1580 


212 100 


1060 571 


1760 


960 


100 212 


530 


986 


870 1598 


400 204 


1080 582 


1780 


971 


200 392 


540 


1004 


880 1616 


420 216 


1100 593 


1800 


982 


210 410 


550 


1022 


890 1634 


440 227 


1120 604 


1820 


993 


220 428 


560 


1040 


900 1652 


460 238 


1140 615 


1840 


1004 


230 446 


570 


1058 


910 1670 


480 249 


1160 626 


1860 


1015 


240 464 


580 


1076 


920 1688 


500 260 


1180 637 


1880 


1026 


250 482 


590 


1094 


930 1706 


520 271 


1200 648 


1900 


1038 


260 500 


600 


1112 


940 1724 


540 282 


1220 659 


1920 


1049 


270 518 


610 


1130 


950 1742 


560 293 


1240 670 


1940 


1060 


280 536 


620 


1148 


960 1760 


580 305 


1260 681 


1960 


1071 


290 554 


630 


1166 


970 1778 


600 316 


1280 693 


1980 


1082 


300 572 


640 


1184 


980 1796 


620 327 


1300 705 


2000 


1093 


310 590 


650 


1202 


990 1814 


640 338 


1320 716 


2020 


1105 


320 608 


660 


1220 


1000 1832 


660 349 


1340 727 


2040 


1116 


330 626 


670 


1238 


1010 1850 


680 360 


1360 738 


2060 


1127 


340 644 


680 


1256 


1020 1868 


700 371 


1380 749 


2080 


1138 


350 662 


690 


1274 


1030 1886 


720 382 


1400 760 


2100 


1149 


360 680 


700 


1292 


1040 1904 


740 393 


1420 771 


2120 


1160 


370 698 


710 


1310 


1050 1922 


760 405 


1440 782 


2140 


1171 


380 716 


720 


1328 


1060 1940 


780 416 


1460 793 


2160 


1182 


390 734 


730 


1346 


1070 1958 


800 427 


1480 804 


2180 


1193 


400 752 


740 


1364 


1080 1976 


820 438 


1500 816 


2200 


1204 


410 770 


750 


1382 


1090 1994 


840 449 


1520 827 


2220 


1216 


420 788 


760 


1400 


1100 2012 


860 460 


1540 838 


2240 


1227 


430 806 


770 


1418 


1110 2030 


880 471 


1560 849 


2260 


1238 


440 824 


780 


1436 


1120 2048 


900 482 


1580 860 


2280 


1249 


450 842 


790 


1454 


1130 2066 


920 493 


1600 871 


2300 


1260 


460 860 


800 


1472 


1140 2084 


940 504 


1620 882 


2320 


1271 


470 878 


810 


1490 


1150 2102 


960 516 


1640 893 


2340 


1283 


480 896 


820 


1508 


1160 2120 


980 527 


1660 904 


2360 


1294 


490 914 


830 


1526 


1170 2138 


1000 538 


1680 915 


2380 


1305 


500 932 


840 


1544 


1180 2156 


1020 549 


1700 927 


2400 


1316 


510 950 


850 


1562 


1190 2174 



Cent. 


Fahr. 


Cent. 


Fahr, 


1200 


2192 


1400 


2552 


1225 


2237 


1425 


2597 


1250 


2282 


1450 


2642 


1275 


2327 


1475 


2687 


1300 


2372 


1500 


2732 


1325 


2417 


1525 


2777 


1350 


2462 


1550 


2822 


1375 


2507 


1575 


2867 






1600 


2912 



288 



TEMPERATURES 

May be determined approximately by reference to the following table 

Degfees Degrees 

Centigrade Fahrenheit 

Just glowing in the dark 525 977 

Dark red 700 1252 

Cherry red 908 1666 

Bright cherry red 1000 1832 

Orange 1150 2102 

White 1300 2372 

Dazzling white , 1500 2732 

Degrees Degrees 

Centigrade Fahrenheit 

Mercury melts 40 104 

Mercury boils 349 660 

Tin melts 229 445 

Lead melts 322 612 

Lead boils 1040 1904 

Zinc melts 412 775 

Zinc boils 1040 1904 

Aluminum melts 700 1252 

Silver melts 957 1775 

Brass melts 1021 . '^ 1870 

Copper melts .^ 1029 1885 

Gold melts 1038 1900 

Cobalt melts 1100 2012 

Cast Iron, white, melts 1135 2075 

Cast Iron, gray, melts r 1222 2230 

Steel melts ,, 1300 2372 

Iron, wrought, melts 1500 2732 

Nickel melts 1500 2732 

Platinum melts ' 2533 4593 

Siemens Crucible Steel Furnace varies from 1230 to 1330 2246 to 2426 



280 



SEGER CONES. 

Seger cones were developed in 1886 in Germany, by Dr. Herman A. 
Seger. They comprise a series of triagular cones, of pyramidical 
shape, of differing mineral compositions, each of which requires a 
different amount of heat work to soften and deform it. They are 
used principally in the clay, pottery and allied industries to deter- 
mine the proper heat conditions of kilns, furnaces, etc. The differ- 
ence in softening point between any two adjoining members of the 
series, is kept as nearly equal as possible, so that the cones form a 
sort of pyrometric scale. The softening or fusion is not altogether 
a matter of temperature, the element of time entering in also. 

The following table gives the approximate fusion points of the 
various cones : 



Number 

of 

Cone 



1 
2 
3 
4 

5 
6 

7 
8 
9 



.022 
.021 
.020 
.019 
.018 
.017 

.016 
.015 
.014 
.013 
.012 

.011 

.010 

.09 

.08 

.07 

.06 
.05 
.04 
.03 
.02 

.01 



Fusing Point 



Degrees 
Fahr, 



1,094 
1,148 
1,202 
1,256 
1,310 
1,364 

1,418 
1,472 
1,526 
1,580 
1,634 

1,688 
1,742 
1,778 
1,814 
1,850 

1,886 
1,922 
1,958 
1,994 
2,030 

2,066 
2,102 
2,138 
2,174 
2,210 

2,246 
2,282 
2,318 
2,354 
2,390 



Degrees 
Centig. 



590 
620 
650 
680 
710 
740 

770 
800 
830 
860 
890 

920 
950 
970 
990 
1,010 

1,030 
1,050 
1,070 
1,090 
1,110 

1,130 
1,150 
1,170 
1,190 
1,210 

1,230 
1,250 
1.270 
1,290 
1,310 



Number 

of 

Cone 



10 

11 

12 
13 
14 
15 

16 
17 
18 
19 
20 

21 
22 
23 
24 
25 

26 
27 
28 
29 
30 

31 
32 
33 
34 
35 

36 
37 
38 
39 



Fusing Point 



Degrees 
Fahr. 



2,426 
2,462 
2,498 
2,534 
2,570 
2,606 

2,642 
2,678 
2,714 
2,750 
2,786 

2,822 
2,858 
2,894 
2,930 
2,966 

3,002 
3,038 
3,074 
3,110 
3,146 

3,182 
3,218 
3,254 
3,290 
3,326 

3,362 
3,398 
3,434 
3,470 



Degrees 
Centig. 



1,330 
1,350 
1,370 
1,390 
1,410 
1,430 

1,450 
1,470 
1,490 
1,510 
1,530 

1,550 
1,570 
1,590 
1,610 
1,630 

1,650 
1,670 
1,690 
1,710 
1,730 

1,750 
1,770 
1,790 
1,810 
1,830 

1,850 
1,870 
1,890 
1,910 



240 



EQUALIZATION OF PIPES. * 

It is frequently desired to know what number of pipes of a given 
?ize are equal in carrying capacity to one pipe of a larger size. The 
figures opposite the intersection of any two sizes is the number of 
the smaller-sized pipes required to equal one of the larger. Thus 
3ne 4-inch pipe is equal to 5.7 2-inch pipes. 



2 
3 
4 

5 
6 
7 
6 
9 
10 
It 
12 
13 
14 
15 
16 
17 
18 
19 
20 
22 
24 
26 
28 
30 
36 


1 

5.7 
15.6 
32.0 
55.9 
88.2 
130 
181 
243 
316 
401 
499 
609 
733 
871 

. • * . 


2 

I 

2.8 
5.7 
9.9 

15.6 

22.9 

32.0 

43.0 

55.9 

70.9 

88.2 

108 

130 

154 

181 

211 

243 

278 

316 

401 

499 

609 

733 

871 


3 

1 

2.1 
3.6 
5.7 
8.3 
11.7 
15.6 
20.3 
25.7 
32.0 
39.1 
47.0 
55.9 
65.7 
76.4 
83.2 
101 
115 
146 
181 
221 
266 
316 
499 
733 


4 

I 

1.7 
2.8 
4.1 
5.7 
7.6 
9.9 
12.5 
15.6 
19.0 
22.9 
27.2 
32.0 
37.2 
43.0 
49.1 
55.9 
70.9 
88.2 
108 
130 
154 
243 
357 
499 
670 
871 


5 

1 

1.6 

2.3 

3.2 

4.3 

5.7 

7.2 

8.9 

10.9 

13.1 

15.6 

18.3 

21.3 

24.6 

28.1 

32.0 

40.6 

50.5 

61.7 

74.2 

88.2 

130 

205 

286 

383 

499 


6 

1 

1.5 

2.1 

2.8 

3.6 

4.6 

5.7 

7.1 

8.3 

.9.9 

11.7 

13.5 

15.6 

17.8 

20.3 

25.7 

32.0 

39.1 

47.0 

55.9 

88.2 

130 

181 

743 


7 

1 

1.4 

1.9 

2.4 

3.1 

3.8 

4.7 

5.7 

6.7 

7.9 

9.2 

10.6 

12.1 

13.8 

17.5 

21.8 

26.6 

32.0 

38.0 

60.0 

88.2 

123 

165 


8 

1 

1.3 

1.7 

2.2 

2.8 

3.4 

4.1 

4.8 

5.7 

6.6 

7.6 

8.7 

9.9 

12.5 

15.6 

19.0 

22.9 

27.2 

43.0 

63.2 

88.2 

118 

154 


9 

I 

1.3 

1 7 

2.1 

2.5 

3.0 

3.6 

4.2 

4.9 

5.7 

6.5 

7.4 

9.3 

11.6 

14.2 

17.1 

20.3 

32.0 

47.0 

62.7 

ftfi ? 


10 

1 

1.3 

1.6 

1.9 

2.3 

2.8 

3.2 

3.8 

4.3 

5.0 

5.7 

7.2 

8.9 

10.9 

13.1 

15.6 

24.6 

36.2 

50.5 

67 8 


12 

1 

1.2 

1.5 

1.7 

2.1 

2 4 

2.8 

3.2 

3.6 

4.6 

5.7 

7.1 

8.3 

9.9 

15.6 

19.0 

32.0 

43.0 

55.9 


14 

1 

1 2 

1.4 

1.6 

1.9 

2.1 

2.4 

3.1 

3.8 

4.7 

5.7 

6.7 

10.6 

15.6 

21.8 

29.2 

38.0 


16 

1 

1.2 

1.3 

1.5 

1.7 

2.2 

2.8 

3.4 

4.1 

4.8 

7.6 

11.2 

15.6 

20.9 

27.2 


18 

1 

1.1 

1.3 

1.7 

2.1 

2.5 

3.0 

3.6 

5.7 

8.3 

11.6 

15.6 

20.3 


20 

I 

1.3 
1.6 
1.9 
2.3 
2.8 
4.3 
6.4 
8.9 
12.0 
15.6 


24 

1 

1.2 
1.5 
1.7 
? 8 


42 






4 1 


48 






5 7 


54 








7,6 


60 






• • • • 


316 


215 


115 


88.2 


9.9 



Table of Necessary Increased Vipe Diameters for Different Lengths 



Length orPtp« 


JO Ft. 


60 Fl. 


00 Ft. 


120 Ft 


150 Ft. 


iSoFt. 


.IiCFl. 


MO Ft 


770 Ft. 

- 


500 Ft 




k. c* 


u c 




4; itJ^ 




t i,£, 


£..}; 


t^% 


t..% 




Diamdei of 


ZE^ 


S.2-a 


i-^' 


t.?-o 


C^fl 


i-^ 


t.E-x 


r.e-^ 


X^. 


le-^ 


Blower Outlet 


= »• = 


H— 3 


Sa-s 


£8.3 


S'-^ 


!°- = 


=*■ = 


=^•3 


E-a 


= •^3 




rew O 


"w 


o«_ 


«<— 


«v. 


.2"- 


2'- 


2>- 


Cw 


,2w 




Q°.-5 


Q^-5 


a°-S 




Q'^-S 


c'^^ 


v^ ox 


Q°^ 


•o«-5 


o^-S 


3 


354 


1,% 


4 


4?4 


4M 


4?< 


5 


.S'r' 


,S>J{ 


.«;?^ 


i'A 


3?i 


4^ 


^)i 


^'^ 


5 


^'A 


<;':< 


."^^^ 


s'A 


t'H 


4 


4>R 


4?-^ 


h% 


^H 


.s^^ 


6 


6}^ 


bY, 


b% 


7, 


4 '4 


5 


.S?« 


^%. 


6 


6% 


6.-^ 


7 


1% 


IH 


7^4 


5 


S'^ 


6 


6,^« 


bH 


1V% 


7.^2 


7^/^ 


^% 


8% 


UK 


6 


(>}4 


7 


7^8 


8 


^M 


9 


9^8 


9% 


»o« 


7 


7*'R 


^)k 


Wz 


9'i^ 


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io:J^ 


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9?4 


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10J4 


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«2>'« 


12% 


tih '3% 


9 


ID 


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«2^ 


« 2:5-4 


>3/'8 


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14.'^ 


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II 


"Xb 


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13H 


14^4 


'4 '"8 


I.^'^ 


'6^ 


i6?4 


nK 


11 


12 


>3 


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14^ 


iS% 


16^^ 


J7^ 


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12 


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17% 


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20^ 


20% 


«3 


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17 H 


i«% 


»9»4 


20^ 


21 


2.% 


22;^^ 


J4 


w/^ 


>6H 


M%, 


iii% 


19^4 


20:!^ 


21% 


22*-^ 


23^ 


2434 


>S 


xbV^ 


«7?i 


'9,, 


20 >^ 


2lJ4 


22?^ 


23J4 


24J4 


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26 


|6 


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20.^ 


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= 2^8 


23^ 


24?i 


2>% 


26% 


27% 
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>7 


'7f^« 


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31 ;^ 


22 3< 


24 


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27'^ 


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= 1?.^ 


22%. 


24 J4 


2%\i 


26^4 


27 /'iJ 


29^ 


3o'i, 


.V34 


19 


20>a 


22 »^ 


24 


2SH 


27 


2S'4 


29M 


3o^< 


3«^« 


33 


20 


22 


^->,% 


25;^ 


27% 


28;*^ 


29^ 


3' 


.32 »4 


3^,'^ 


.34 T^ 


31 


23 


W/z 


26 i^ 


2iiM 


29-'4 


3'^ 


32'^ 


33>^ 


v^'4 


3^.^8 


22 


24^ 


26^ 


21>A 


29\i 


l^h 


32 H 


34^ 


.35'^ 


.^6V/« 


3^J^ 


23 


253-4^ 


27M 


29^ 


.30>i 


y-'A 


34'8 


.3.sy« 


37^ 


38.'< 


39>^ 


24 


c6f^ 


2%y^ 


30,^« 


32K 


^-^ , 


35 ?1. 


ZIVa 


?>^% 


40>4 


4>>8 


Length of Pip^ 


30 Ft. 


60 Ft. 


90 It. 


120 ft. 


j:;o ft. 


tSo tt 


210 tt. 


240 It 


:70 It. 


300 u. 
60 in 


Length ot Mouth-piece 


9 in 


15 in 


21 in 


27 in 


35 »" 


39 i" 


42 in 


48 in 


54 in 



241 





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242 



VOLUME OF AIR DISCHARGED AT LOW PRESSURES 

PER MINUTE. 



Diam. of 
Openings in. 


8oz 


16oz 


24oz 


32oz 


40oz 


48oz 


■ 

56oz 


64oz 


% 


cu.ft. 

3.5 


cu.ft. 

4.5 


cu.ft. 

5.5 


cu. ft. 

6.5 


cu.ft. 

7.5 


cu. ft. 

8 


cu.ft. 
9 


cu.ft. 
9.5 


H 


7 


8 


12.5 


14.5 


16.5 


18 


20 


21.5 


K 


12.5 


17.5 


22 


25.5 


29 


32.5 


35.5 


39.5 


H 


19 


29 


34 


40 


45.5 


50.5 


55.5 


60 


H 


27.5 


39.5 


49 


57.5 


65.5 


72.5 


79.5 


^d 


yi 


37.5 


54 


67 


78.5 


89 


98.5 


108 


118 


1 


49 


70 


87 


103 


116 


128 


141 


153 


1 H 


62 


89.5 


HI 


130 


147 


163 


179 


194 


IK 


76.5 


110 


135 


160 


181 


201 


220 


239 


IH 


92.5 


132 


164 


193 


218 


243 


266 


289 


IK 


lid 


157 


196 


233 


260 


289 


317 


244 


IK 


150 


214 


266 


312 










2 


195 


280 


348 


409 










IVz 


345 


437 


545 


638 


1 
1 







This table may be used for estimating the amount of air flowing 
thru any size pipe by finding the square inch area of the pipe and 
multiplying this by the figure in the horizontal line with the 1%" 
opening, which corresponds to the pressure. Example : 

A 10" pipe has an area of 78.54 sq. in., if the pressure is found to 

be 32 ounces, multiply- 

78.54 

xl30 



235620 

7854 



10210.20 cu. ft. of air flowing thru a 10'' 
pipe into the atmosphere at a pressure of 32 ounces in the pipe per 
minute. 

Note: The l^s-inch size is used as this has an area of ap- 
proximately 1 square inch. 

243 



AIR REQUIRED TO VENTILATE SAND BLAST ROOMS. 

Suction fans are used to ventilate sand blast rooms. 

The suction side of the fan is connected to the sand blast chamber 
and the discharge end of fan opening to the atmosphere. 

The air in a sand blast room should be changed from three to four 
times per minute. Example : 

Assume the room is 8 x 8 x 7 ft. high. Then, the cubic feet in 
the room will be 448 ; alloAving 4 changes per minute — 448 x 4 equals 
1792 cu. ft. of air must be eliminated per minute. A fan having this 
capacity should be selected. 

Note : — Be sure to allow 1792 cu. ft. of air to enter room thru 
suitable openings. 

DISTANCE BETWEEN PULLEY CENTERS 

When installing belt driven equipment, it is often desired to 
know the best distance betw^een centers of pulleys — the table here 
given may be used as a guide providing no idlers are used. 



^BNTEff Jo C^NT^ff Or PULL£Y^ 






VJiDTH 


Center TbCeNrEffOrFi/iLEYs 




/HtNlMUM 


/OEffL . 


JfJfjxiMUfn 




v3 /VC//. 


^Tee-r- 


STebt 


^sT^^T 




6 „ 


6 /. 


/a o 


r 

30 „ 




/a .. 


9 " 


/7 n 


3a „ 




J 8 /. 


// - 


20 /. 


3A " 




24 n 


/Z .. 


ea n 


37 « 



244 



HOW TO READ A MICROMETER. 





A— Frame 

B-AnvU 

C— Spindle or Screw 

D- Sleeve or Barrel 

E- Thimble 



—Micrometer. 



The various parts of a micrometer are known as follows : 

Frame A 

Anvil B 

Spindle C 

Sleeve D 

Thimble E 

The object to be measured is placed between the anvil B and 
spindle C. The spindle C is capable of being moved in or out, 
having a thread cut on its circumference which passes thru the 
inside of sleeve D. To the right hand end of spindle C is 
fastened thimble E which is hollow and passes over sleeve D. 

The thread cut on the spindle C has 40 threads per inch 
therefore by revolving the thimble E one complete revolution, 
the spindle C will advance 1/40 of 1 inch and four revolutions 
will advance the spindle 4/40 or 1/10 of an inch. This distance is 
represented between the and the 1 on the sleeve D. Each 
smaller division between the and the 1, represents 1/40 or .025 
of an inch. 

The thimble E has 25 equal divisions around its circumfer- 
ence, each division representing 1/25 of 1/40 inch, or .001 inch. 

To read the distance between the anvil B and spindle C, 
add the number of divisions visible on the sleeve D — multiply 
this by .025 and then add to this .001 for each division on thimble 
E that has passed the upper horizontal line on sleeve D. 

The micrometer now reads: 

.025 X 7 == .175 on D 
.001 X 3 = .003 on E 



.178 answer 

Note : — By close observation it will be seen that six divisions only 
are visible on sleeve D. However the on thimble E has 
passed the upper horizontal line on sleeve D, indicating that the 
seventh division has been passed. 

245 



J 


\CHORC. 


3 

i TO 


FIND THE LENGTH OF A CHORD WHICH WILL 
rim THE CIRCUIIFERSNCE INTO "N" EQT[JAL 
^TS --- MULTIPLY THE DIAIJETER BY "S". 




^^ 


-^ r)i\ 


\ 


O}"" 


// PAI 








N 


s 


N 


S 


N 


S 


N 


S 


1 


.00000 


26 


.12054 


51 


.061560 


76 


.041325 


2 


.10000 


27 


.11609 


52 


.060379 


77 


.040708 


3 


.86603 


28 


.11197 


53 


.059240 


78 


.040267 


4 


.70711 


29 


.10812 


54 


.058145 


79 


.039757 


5 


.58779 


30 


.10453 


55 


.057090 


80 


.039260 


6 


.50000 


31 


.10117 


56 


.056071 


81 


.038775 


7 


. 43388 


32 


.098018 


57 


.055089 


82 


.038 303 


8 


.38268 


33 


.095056 


58 


.054139 


83 


.037841 


9 


.34202 


34 


092269 


59 


,053222 


84 


.037391 


10 


.30902 


35 


.089604 


60 


.052336 


85 


.036953 


11 


.28173 


36 


.087156 


61 


.051478 


86 


.036522 


12 


.25882 


37 


.08 4804 


62 


.050649 


87 


.036103 


13 


.23932 


38 


.082580 


63 


.049845 


88 


.035692 


14 


.22252 


39 


.080466 


64 


.049068 


89 


.035291 


15 


.20791 


40 


.078460 


65 


.048312 


90 


.034899 


16 


.19509 


41 


.076549 


66 


.047582 


91 


.034516 


17 


.18375 


42 


.074731 


67 


.046872 


92 


.034141 


18 


.17365 


43 


.072995 


68 


.046184 


93 


.033774 


19 


.16460 


44 


.071339 


69 


.045515 


94 


.033415 


20 


.15643 


45 


.069756 


70 


.044865 


95 


.033064 


21 


.14904 


46 


.068243 


71 


.044232 


96 


.032719 


22 


.14232 


47 


.067093 


72 


.043619 


97 


.032381 


23 


.13617 


48 


.065401 


73 


.043022 


98 


.032051 


24 


.13053 


49 


.064073 


74 


.042441 


99 


.031728 


25 


.12533 


50 


.062791 


7^ 


.041875 


100 


.031411 



246 



HOW TO USE THE CHORD TABLE 

The shortest distance between any two adjacent points on the 
circumference of a circle is kno\^Ti as the chord. Assume the cir- 
cumference of a circle 54" in diameter is to be divided into 14 equal 
parts, this may be found as follows : 

N = 14 (see table) 
S=.22252 (see table) 
Dia. = 54 inches 

Multiply S X DIA. = .22252 x 54 = 12.01 inches. 



EXAMINATION 
LESSON 24 

1. At what temperature F. does brass melt? 

2. How many 8-inch diameter pipes will it take to equal the same 
carrying capacity as a 20-inch pipe? See table. 

3. HoAv much air per minute will be discharged from a receivcF 
thru a i/^-inch opening into the atmosphere if the pressure in 
receiver is 40 lbs? 

4. How much air at 16 oz. pressure will be discharged thru an 
18-ineh pipe? See table and text. 



247 



CONTENTS 



LESSON ONE Page 

Importance of careful study . 5 

What is a working drawing? 5 

Working drawings classified? ........... 5 

Lines .......' 6 

Description of lines appearing on working drawings .... 7 

ELinds of drawings 8 

Shaded lines 9 

Line shading 10 

Examination . 11 

LESSON TWO 

Imagination a valuable asset 13 

Developing the imagination 14 

Care in the making and reading of working drawings ... 15 

Position of eye for working drawing views 15 

Illustration explaining the projection of a depressed surface . . 18 
Another example illustrating the position of eye for working 

drawing views '. . 20 

Examination 21 

LESSON THREE 

Projections 23 

Method of projecting working drawing views 25 

Points or surfaces projected horizontally 29 

Points or surfaces projected vertically 30 

Examination . 33 

LESSON FOUR 

Cross sectional view (how produced) 35 

Rearrangement of views 36 

Projections of circular objects 36 

Examination . 41 

LESSON FIVE 

Working drawing views of two separate objects combined . . 43 

Perspective views not shown on working drawings . . . . 46 

Description of geometrical figures and solids 46 

Description of instruments and tools • . . 48 

Examination 51 

LESSON SIX 

Explanation of notations appearing on working drawings . . 53 

Scales 56 

Cross sections and crosshatching 57 

Examination 59 

LESSON SEVEN 

Method of indicating cross sections 61 

Zigzag cross sections 62 

Half and quarter cross sections 63 

Bolts, threads and taps 64 

Shrink rule — explarlation and use 65 

The measurement of angles • . . 66 

Chaplet (working drawing) 67 

Examination . 69 

249 



CONTENTS 



LESSON EIGHT Page 

Method illustrated of bringing all extensions and depressions to 

the same plane . 71 

Drawings analyzed: 

Screw driver 72 

Wrench . 72 

Standard elbow 73 

Mallet ..*.'. 74 

Perspective drawings of molders' tools 75 

Examination 77 

LESSON NINE 

Drawings analyzed: 

Wood flask 79 

Iron flask 80 

Shank 82 

Perspective and working drawing views of a foundry flask . . 80 

Single view drawing, tensile test bars 83 

Number of views necessary 84 

Three view drawings 84 

Examination . 85 

LESSON TEN 

Drawings analyzed: 

Chill rolls . 87 

Bearing bracket 88 

Saw horse 90 

Mold for pouring basin 91 

Friction disc 93 

Examination 94 

LESSON ELEVEN 

Drawings analyzed: 

Clamp 95 

Shaft coupling 96 

Bearing 100 

Free hand sketching 97 

» Dimension lettered drawings 98 

Specifications 101 

Examination 102 

LESSON TWELVE 

Practice reading 103 

Review . 104 

Drawings analyzed: 

Bearing cup 104 

Gear wheel . . ' 107 

Punching (single view drawing) 109 

Center rest top Ill 

Angular projections 112 

Illustrating use of limit dimensions 109 

Examination ..." 113 

250 



CONTENTS 



LESSON THIRTEEN Page 
Drawings analyzed: 

Piston . 115 

Base 117 

Cupola 121 

Motor frame 122 

Beehive coke oven 125 

Operation of beehive coke oven 125 

Examination 127 

LESSON FOURTEEN 
Drawings analyzed: 

Bottom pour ladle . 129 

Typical detail drawing 133 

Tilting mechanism for electric furnace 135 

Name of parts of tilting mechanism 137 

Examination 137 

LESSON FIFTEEN 
Drawings analyzed: 

Gagger casting machine 139 

Pump base 141 

Annealing boxes 143 

Molding and pouring nails 144 

Sectional view of slagging spout 145 

Slagging spout 145 

Malleable iron furnace , . . . . 149 

Examination 150 

LESSON SIXTEEN 

Melting furnaces 151 

Blast furnace 153 

Description of hot blast stoves 155 

Side blow converter 155 

Bessemer converter 157 

Open hearth furnace 159 

Acid and basic melting . 161 

Examination 162 

LESSON SEVENTEEN 

Process of making a blue print 163 

Electric furnace 165 

Plant layout drawings 167 

Diagrammatic drawings 169 

Diagrammatic wiring drawing 170 

Repair part drawings 170 

Valve body 173 

Patent office drawings 174 

Examination 177 

LESSON EIGHTEEN 

Weights and measures 180-181 

Fractions of an inch and equivalent decimals 1<S2 

How to use decimals 182 

Addition of decimals 183 

Subtraction of decimals 183 

Multiplication of decimals 184 

Division of decimals 185 

Proof of division 187 

Examination 187 

251 



CONTENTS 

LESSON NINETEEN Page 

Areas of squares and circles 189 

Volume of cubes 189 

Volume of spheres ^ _ 191 

Weight of balls . . . . 191 

Circumference and areas of circles for different diameters . 192-196 

Formulas , 197 

Examination " . . 199 

LESSON TWENTY 

Areas and volumes of various shaped figures and objects . . 201-205 
How to estimate the weights of various shaped objects when made 

of difl:erent materials 205 

Solid block, rod, hollow cylinder — cubic inches in ... . 205-207 

Estimating weight of casting from pattern • . . 208 

Examination ... * 209 

LESSON TWENTY-ONE 

Method of estimating the weight of a casting from drawing . , 211 

Estimating the weight of cast iron fly wheel 214 

Examination 218 

LESSON TWENTY-TWO 

Specific gravity, definition and tables 219 

Specific gravity of miscellaneous substances . . . . . . 220 

Specific gravity and average weights per cubic foot of wood . . 221 

Specific gravity of gases 221 

Specific gravity of liquids 221 

How to read "U" gauges 222 

Curve or graph readings 223 

Shrinkage of castings per foot 224 

Capacity of cylindrical tanks 225 

Board feet in pattern lumber 226-227 

General information about fire brick 228 

Refractory bricks (shapes and sizes) 229 

Examination 230 

LESSON TWENTY-THREE 

Safe loads for ropes and chains 231 

Useful information giving the heat units, weights per cubic foot 

and space occupied by various fuels 232 

Weights in pounds of square and round cast iron plates, 1" thick 233 

Weights of round and square steel 234 

How to use table for cast iron 234 

Examination 235 

LESSON TWENTY-FOUR 

Thermometer scales 237 

Temperatures — degrees Fahrenheit and Centigrade 238 

Temperatures (by color) 239 

Temperatures (melting of metals) 239 

Seger cones . 240 

Equalization of pipes 241 

Volume of air discharged thru an orifice (2 lbs. to 90 lbs. pressure) 242 

Volume of air discharged at low pressure 243 

Air required to ventilate sand blast rooms 244 

Distance between pulley centers 244 

How to read a micrometer 245 

Chord table 246 

How to use the chord table 247 

Examination 247 

252 



TABLES 

Page 

Weights and measures 180-181 

Fractions of an inch and equivalent decimals 182 

Circumference and areas of circles 192-196 

Weight of casting from pattern 208 

Specific gravity of metals . 219 

Weight per cu. in. in pounds 219 

Specific gravity of miscellaneous substances and weights per 

cu. ft. pounds 220 

Specific gravity of wood and weight per cu. ft 221 

Specific gravity of gases 221 

Specific gravity of liquids 221 

Ounces pressure per square inch for inches of WATER in "U" 

gauge 222 

Ounces pressure per square inch for inches of MERCURY in "U" 

gauge 223 

Shrinkage of castings per foot 224 

Capacity of cylindrical tanks 226 

Board feet in pattern lumber 226-227 

Safe load for ropes and chains 231 

Heat units, weights per cubic foot and space occupied by various 

fuels . . 232 

Weight in pounds of square and round cast iron plates, 1" thick 233 

Weights of round and square steel 234 

Temperatures — Degrees Fahrenheit and Centigrade 238 

Temperature (melting of metals) 239 

Temperature (by color) 239 

Seger cones 240 

Equalization of pipes '. 241 

Volume of air discharged thru round orifice (2 to 90 lbs. pressure) 242 

Volume of air discharged at low pressure per minute .... 243 

Distance between pulley centers 244 

Chord lengths of circles for various divisions of the circumference 246 



253 



